Events

Events (some also known as invasions) are temporary occasions where varieties of special enemies spawn, most at elevated spawn rates, even near NPCs, and attack players. Some events can occur randomly during gameplay, while others can be triggered via certain summoning items or special circumstances. Events spawn their own unique enemies not seen during ordinary gameplay, which can, in turn, drop unique items that are only obtainable within the event. Some events also bring unique visuals and a unique atmosphere, such as an altered moon and noticeable shaders applied to the screen. Events also are accompanied by their own special music, adding on to their theme. Depending on the particular event, they may last until a certain time limit is reached, or until a certain number of enemies are defeated.
On the Desktop version,
Console version, and
Mobile version, a progress bar can be seen during certain events, which indicates the player's progression in the event and how far they are from completing it. It only appears during these events: Goblin Army, Old One's Army(Desktop, Console and Mobile versions), Frost Legion, Pirate Invasion, Pumpkin Moon, Frost Moon, and Martian Madness(Desktop, Console and Mobile versions). Other time-limited events (Blood Moon, Rain, Slime Rain(Desktop, Console and Mobile versions), Sandstorm(Desktop, Console and Mobile versions), Solar Eclipse, etc.) do not have a progress bar. See Notes for more details about the progress bar.
Invasion-type events have location requirements. The player must be no deeper than 67.5 tiles below the surface and within 187.5 tiles horizontally of the location of the invasion to be considered in the range of it, otherwise no invasion enemies will spawn. If the invasion is near the horizontal world center, then the horizontal check can also be satisfied by the player being within 187.5 tiles horizontally of any town NPC, although at a reduced spawn rate. The town NPC's vertical position is not checked and so they can be housed far above or below the arena. See Notes for more details about invasions.
There are (Desktop, Console and Mobile versions)19 / (Old-gen console and 3DS versions)8 different events.
Peaceful events

- Initiated randomly by NPCs during the day, or by manually activating a
Party Center.
During a Party, most NPCs, town pets, the Travelling Merchant, and even Bunnies can be seen wearing a Party Hat. NPCs will display unique dialog when spoken to and some will sell unique items.
While a Party is going on, different colored balloons are floating all around the sky in the background.
The event will always end on dusk.

- Occurs the night after a boss or invasion has been defeated for the first time, or randomly at night after the Moon Lord has been defeated.
The Lantern Night is an event that occurs in celebration of the player's victory over a boss or invasion. The Party Girl will sell the Release Lantern and the player will have a flat +0.3 increase to their Luck stat.
During such a night many lanterns can be seen rising up into the sky in the background.
Weather events

- Occurs randomly.
Rain affects all surface biomes for its duration. Each Rain event can last anywhere from a few in-game hours to several in-game days, potentially spanning both day and night portions. When a player is in a Snow biome during Rain, it appears as a Blizzard, causing snowfall volume to increase. Rain also increases cloud cover.
Deerclops(Desktop, Console and Mobile versions)(rare)
Angry Nimbus(uncommon)
Rainbow Slime(The Hallow, rare)
Ice Golem(rare)
Other effects include the following:

- Occurs randomly while Wind speeds are above 30 mph.
A Sandstorm is an event specific to the Desert, they will not occur anywhere else. A Sandstorm occurs in all Deserts at the same time. While this event is active, the Mighty Wind debuff will be continuously inflicted upon the player.
During a Sandstorm, many particles of sand can be seen flying across the screen, the color of these particles will depend on whether the Desert is regular, Corrupt, Crimson, or Hallow. Vision is also limited.

- Occurs randomly.
A Windy Day results in increased cloud cover and stronger wind effects. If a Windy Day happens at the same time as a Rain, the result is a Thunderstorm.
In addition to regular Forest surface enemies, the following enemies will spawn:

- Occurs randomly.
A Thunderstorm is a rare weather event where both the Rain and Windy Day events combine. During a Thunderstorm, lightning will occasionally flash on the screen and the lighting will dim even further than the Rain. The wind also blows much more ferociously than normal. All effects from the Rain event also occur during a Thunderstorm.

- Occurs randomly at night.
A Meteor Shower is an event during which falling stars appear all throughout the sky in the background. Meteor Showers greatly increase the spawn rate of Fallen Stars, and causes Enchanted Nightcrawlers to spawn, resulting in easily obtainable bait.
Pre-Hardmode events

- Occurs with a 1/9 (11.11%) chance if at least one player in the world has more than 120 health and when it is not a new moon, or when manually summoned with a
Bloody Tear(Desktop, Console and Mobile versions).
A Blood Moon is an event that takes place over the course of an entire night, from 7:30 PM to 4:30 AM, affecting only the surface layer.
Blood Moons are signaled by the status message "The Blood Moon is rising...". All the water in the world, even underground, will turn blood-red for the duration of the event, including rain and the moon itself. (Desktop, Console and Mobile versions) A red filter will be applied to the screen when the player is on the surface layer. The ability to speed up time by sleeping in a bed is also disabled.
The event will significantly boost spawn rates in surface biomes, as well as spawn new and dangerous enemies, while also changing their behavior and spawning conditions.
(Desktop, Console and Mobile versions) Fishing Power is increased by 1.1 times. However, fishing could also bring about unique enemies.
The Groom
The Bride(Desktop, Console and Mobile versions)
Blood Zombie(Desktop, Console and Mobile versions)
Drippler(Desktop, Console and Mobile versions)
Vicious Bunny(Desktop, Console and Mobile versions)
Vicious Goldfish(Desktop, Console and Mobile versions)
Vicious Penguin(Desktop, Console and Mobile versions)
Wandering Eye Fish(Desktop, Console and Mobile versions)
Zombie Merman(Desktop, Console and Mobile versions)
Clown
Chattering Teeth Bomb(Desktop, Console and Mobile versions)
Hemogoblin Shark(Desktop, Console and Mobile versions)
Blood Eel(Desktop, Console and Mobile versions)
Dreadnautilus(Desktop, Console and Mobile versions)
Blood Squid(Desktop, Console and Mobile versions)

- Has a 1/3 (33.33%) chance of occurring every dawn if at least one
Shadow Orb /
Crimson Heart has been destroyed and when a player has over 200 health. Can also manually be summoned with a
Goblin Battle Standard.
The Goblin Army is an event where unique Goblin enemies spawn. When a Goblin Army is approaching, one of the two following status messages will appear: "A goblin army is approaching from the west!" / "A goblin army is approaching from the east!"
Goblin Warlock(Desktop, Console and Mobile versions)
Shadowflame Apparition(Desktop, Console and Mobile versions)(from Goblin Warlock)
Although they do not appear in the Goblin Army, Goblin Scouts can be found rarely on the outer thirds of the map. They drop Tattered Cloth which is used to craft the Goblin Battle Standard, the summoning item for this event.
The event is completed after a certain number of goblins have been defeated. Afterward, the Goblin Tinkerer NPC can be found underground.

- Occurs when a player has over 140 health and 8 defense, except in Expert Mode, where it can occur with a significantly decreased chance before meeting the criteria.
Slime Rain is an event where different variations of slimes constantly fall from the sky. If the player kills 150 slimes before the event ends naturally, King Slime will spawn. If King Slime was defeated previously, then only 75 slimes need to be killed before he spawns.
Many types of slimes spawn, including:
After King Slime is defeated, the event will immediately terminate.

- Initiated by placing an
Eternia Crystal on an
Eternia Crystal Stand.
The Old One's Army is a unique Dungeon Defenders 2 crossover event that can be initiated after rescuing the Tavernkeep, who can be found on any layer after defeating the Eater of Worlds/Brain of Cthulhu. The objective is to protect the Eternia Crystal from waves of enemies which appear from Mysterious Portals, seeking to destroy it. If the Crystal is destroyed by enemies, the event terminates. If it is kept safe until all waves are cleared, the event is won.
Both the Crystal and its Stand are purchased from the Tavernkeep NPC for coins. Players are inflicted with the Creative Shock debuff for the duration of the event, which prevents the removal or placement of blocks during the entire event within a certain range.
Each wave becomes progressively more difficult and features larger varieties of enemies. Additionally, the entire event is expanded in difficulty depending on player progression. If triggered before any Mechanical Bosses have been defeated, the event consists of 5 waves. If triggered after at least one Mechanical Boss is defeated, the event consists of 7 waves. Once Golem has been defeated, the event becomes even more difficult with the boss Betsy spawning in the final wave. Betsy will only spawn once during each event, and defeating her will complete the event. The event also contains 2 mini-bosses; the Ogre and the Dark Mage.
Mysterious Portal(Desktop, Console and Mobile versions)
Etherian Goblin(Desktop, Console and Mobile versions)
Etherian Goblin Bomber(Desktop, Console and Mobile versions)
Etherian Javelin Thrower(Desktop, Console and Mobile versions)
Etherian Wyvern(Desktop, Console and Mobile versions)
Dark Mage(Desktop, Console and Mobile versions)
Old One's Skeleton(Desktop, Console and Mobile versions)(from Dark Mage)
Kobold(Desktop, Console and Mobile versions)
Drakin(Desktop, Console and Mobile versions)
Kobold Glider(Desktop, Console and Mobile versions)
Wither Beast(Desktop, Console and Mobile versions)
Ogre(Desktop, Console and Mobile versions)
Etherian Lightning Bug(Desktop, Console and Mobile versions)
Betsy(Desktop, Console and Mobile versions)

- Initiated when around 100 torches accumulate in close proximity anywhere below the surface layer.
The Torch God is a mini-event that happens when 100 torches accumulate in close proximity underground. The placed torches begin launching small fireballs at the player, extinguishing themselves in the process. The fireballs deal 40 / 80 / 120 damage, and they travel in straight lines through blocks. They can also spawn from torches located off-screen.
While the event is active, the player is inflicted with the Blackout debuff, significantly reducing the player's light vision.
When all torches are extinguished, the event ends. After a brief period, the torches reignite, and if 100 or more torches have been activated, the Torch God's Favor will appear in the player's inventory. The player can not challenge the event again once the player has a Torch God's Favor either in their inventory or consumed, and must create another character to do so. A player that has not consumed a Torch God's Favor can continuously challenge and complete the event and obtain more Torch God's Favors, as long as they do not have one in their inventory.
Hardmode events

- Summoned with a
Snow Globe.
The Frost Legion is an event that functions similarly to the Goblin Army, but it requires an item to start the event, which is only attainable in Hardmode. During Christmas, enemies will drop presents. If the world is in Hardmode, these presents have a 1/13 (7.69%) chance of containing a Snow Globe, which is used to spawn the Frost Legion.
During the event, three different types of unique snowmen will spawn:
All of the snowmen drop Snow Blocks, technically granting the player a way to obtain infinite amounts of Snow.
The event is completed after a certain number of snowmen have been defeated. Afterward, the Santa Claus NPC will spawn during Christmas.

- Occurs with a 1/20 (5%) chance each day upon dawn, as soon as any mechanical boss has been defeated, or when manually summoned with a
Solar Tablet(Desktop, Console and Mobile versions).
The Solar Eclipse is a Hardmode event where the sun will rise, obscured by the moon, dramatically reducing natural light to a level darker than nighttime. Normal biome enemy spawns are replaced with special enemies that can spawn near NPCs, much more frequently and in greater numbers than usual.
During the event, the following enemies will spawn:
Swamp Thing
Frankenstein
Eyezor
Vampire
The Possessed(Desktop, Console and Mobile versions)
Fritz(Desktop, Console and Mobile versions)
Creature from the Deep(Desktop, Console and Mobile versions)
Reaper((Old-gen console and 3DS versions))
After all three mechanical bosses have been defeated:
Reaper((Desktop, Console and Mobile versions))
After Plantera has been defeated:
Butcher(Desktop, Console and Mobile versions)
Nailhead(Desktop, Console and Mobile versions)
Deadly Sphere(Desktop, Console and Mobile versions)
Psycho(Desktop, Console and Mobile versions)
Dr. Man Fly(Desktop, Console and Mobile versions)
Mothron(Desktop, Console and Mobile versions)
Baby Mothron(Desktop, Console and Mobile versions)
A Solar Eclipse is always terminated upon dusk.

- Occurs randomly during the day if a player has over 200 health, or when manually summoned with a
Pirate Map.
The Pirate Invasion is an event that is very similar to the Goblin Army. It can spawn randomly, or be summoned by the use of a Pirate Map, which can be obtained from killing any enemy in the Ocean biome during Hardmode.
During the event, (Desktop, Console and Mobile versions)7 / (Old-gen console and 3DS versions)6 different pirate themed enemies will spawn:
Pirate Deckhand
Pirate Deadeye
Pirate Corsair
Pirate Crossbower
Pirate Captain
Parrot
Flying Dutchman(Desktop, Console and Mobile versions)
The event is completed after a certain number of pirates have been defeated. Afterward, the Pirate NPC will move in.

- Summoned at night with a
Pumpkin Moon Medallion.
The Pumpkin Moon is a Halloween-themed event that lasts until the next dawn. Unlike most other events, the Pumpkin Moon takes place in distinct waves. Each wave is finished by getting enough points by defeating enemies, with higher waves having higher difficulty. If enough enemies are defeated, the event will eventually enter the final wave where event enemies spawn endlessly.
During the event, the moon visually turns into a jack-o-lantern.
The Pumpkin Moon has seven unique enemies, in increasing order of difficulty:
Although there are no rewards for surviving the event, besides an achievement, the enemies can drop unique items, including Spooky Wood and equipment like the Spooky Hook and Raven Staff.

- Summoned at night with a
Naughty Present.
The Frost Moon is a Christmas-themed event that lasts until the next dawn and uses the same wave system as the Pumpkin Moon. Enemies have similar behavior to Pumpkin Moon counterparts, but are tougher, making this event the hardest on the Old-gen console version and Nintendo
version.
During the event, the moon visually turns into a snowman's face.
The Frost Moon has 11 unique enemies:
Although there are no rewards for surviving the event, besides an achievement, the enemies can drop unique items.

- Initiated by letting a
Martian Probe escape from view after detecting a player.
The Martian Madness event is a post-Golem event with an alien invasion theme. This event is unique from the others in that in order to start it, it is required to encounter a Martian Probe randomly in the surface and space layers of the world and move into its light. Once the Martian Probe detects the player, it needs to leave the screen without being destroyed.
During the event, UFOs can be seen flying in the background.
The Martian Madness event features 11 unique enemies:
The event is completed after a certain number of Martians have been defeated.

- Initiated after defeating the Lunatic Cultist.
The Lunar Events is a unique type of event that spawns four different pillars, the Celestial Pillars, spread evenly across the world. While in the proximity of a pillar, respectively-themed enemies spawn. There are four different pillars: the Solar Pillar, the Vortex Pillar, the Nebula Pillar, and the Stardust Pillar. Initially, all pillars are surrounded by a protective shield. In order to damage and eventually defeat a pillar, a certain number of enemies related to said pillar needs to be defeated.
There are numerous unique enemies in this event:
After defeating all four pillars, the Moon Lord will spawn. The event is completed once the Moon Lord is defeated or the player dies during the battle.
Notes
- Some events are classified as "invasions" and have their respective "invasion ID"[1] internally. Only one invasion can happen at a time. When an invasion is active, attempts to start other invasions will fail. Invasions also have the following features:
- Most invasions start at left or right world border and take some time to move to the world spawn point. Invasions move at the speed of 1 tile per tick[2], or 60 tiles per second ((Desktop, Console and Mobile versions) which is affected by time speed, e.g. time slider in Journey Mode, Enchanted Sundial, sleeping).[3] Assuming the world spawn point is at the horizontal center of the world, invasions take 35, 53, and 70 seconds to reach spawn point in small, medium, and large world size, respectively.
- The status message informing the player about an incoming invasion (e.g. "A goblin army is approaching from the west!" for Goblin Army) will be displayed once per minute before the invasion reaches spawn point. As a result, the message will be displayed twice in large worlds.
- Unlike other invasions, the Martian Madness starts at world spawn point, so event enemies can immediately begin spawning after the invasion started.
- As said above, the player must be no deeper than 67.5 tiles below the surface and within 187.5 tiles horizontally of the location of the invasion to be considered in the range of it, otherwise no invasion enemies will spawn. The horizontal check can also be satisfied by the player being within 187.5 tiles horizontally of any town NPC, although having reduced enemy spawn rate, if the invasion has reached no more than 5 tiles from the horizontal center of the world.
- The town NPC's vertical position is not checked.
- The player has to kill enough enemies to complete the invasion. For each exising player, the required kill count is increased by a fixed amount. The formulas are shown in the table below.[4]
- Most invasions start at left or right world border and take some time to move to the world spawn point. Invasions move at the speed of 1 tile per tick[2], or 60 tiles per second ((Desktop, Console and Mobile versions) which is affected by time speed, e.g. time slider in Journey Mode, Enchanted Sundial, sleeping).[3] Assuming the world spawn point is at the horizontal center of the world, invasions take 35, 53, and 70 seconds to reach spawn point in small, medium, and large world size, respectively.
Invasion ID Required kill count (No invasion active) 0 Goblin Army 1 [math]\displaystyle{ 80+40\times\text{Player count} }[/math] Frost Legion 2 [math]\displaystyle{ 80+40\times\text{Player count} }[/math] Pirate Invasion 3 [math]\displaystyle{ 120+60\times\text{Player count} }[/math] Martian Madness(Desktop, Console and Mobile versions) 4 [math]\displaystyle{ 160+40\times\text{Player count} }[/math]
- On the Nintendo
version, the music for invasions is played throughout the entire world, regardless of if there are any enemies until it has been cleared.
- The display mode for progress bar for events can be changed in settings, with 3 options available: On, Off, or Timed.
- On: Default option. The progress bar will be displayed if any event-related enemy is within a rectangular area centered on player with a size of about 384.5×384.5-tile.[5] For Pumpkin Moon, Frost Moon, or invasions, it also requires the player to be above surface layer. When the conditions are not met, the progress bar will be hidden after 2.67 seconds.
- Off: The progress bar will not be displayed.
- Timed: The progress bar will be displayed for 2.67 seconds after killing an event-related enemy, or the event progresses to the next wave. The remaining display time refreshes after said condition is met again.
Achievements






















Trivia
- The Party(Desktop, Console and Mobile versions) and the Lantern Night(Desktop, Console and Mobile versions) are the only events that do not spawn unique enemies nor play special music.
History
- Desktop 1.4.0.5: The Torch God event added.
- Desktop 1.4.0.1: Windy Day, Thunderstorm, Meteor Shower, and Lantern Night events added.
- Desktop 1.3.4: Old One's Army event added.
- Desktop 1.3.3: Sandstorm event added.
- Desktop 1.3.2: Party event added.
- Desktop 1.3.0.1:
- Martian Madness, Slime Rain, and Lunar Events added.
- Certain events now have a progress bar, showing how far along the player is towards completion.
- Event enemies now run away when the event is over.
- Desktop 1.2.4:
- Fixed bug where spawn rates would increase underground when a moon event is happening.
- Invasion summon items will no longer be consumed if no invasion would happen using it.
- Desktop 1.2.3: Invasions can now spawn enemies anywhere near friendly NPC instead of just the middle of the world.
- Desktop 1.2: Solar Eclipse, Rain, and Pirate Invasion events added.
- Desktop 1.1.1: Frost Legion event added.
- Desktop-Release: Introduced Goblin Army and Blood Moon.
- Switch 1.0.711.6: Introduced Goblin Army, Blood Moon, Frost Legion, Solar Eclipse, Rain, Pirate Invasion, Martian Madness, Slime Rain, and Lunar Events.
- Console-Release: Introduced Goblin Army, Blood Moon, and Frost Legion.
- Mobile 1.3.0.7: Introduced Slime Rain, Martian Madness, and Lunar Events.
- Mobile-Release: Introduced Goblin Army, Blood Moon, and Frost Legion.
- 3DS 1.03: Frost Moon Added.
- 3DS-Release: Introduced Goblin Army, Blood Moon, Frost Legion, Solar Eclipse, Rain, Pirate Invasion, and Pumpkin Moon.
References
- ↑ Information taken from the
Desktop 1.4.4.9 source code, field
invasionType
inTerraria.Main.cs
. - ↑ A tick is a time unit countable by the software. Most of Terraria's updating logic happens every tick. A tick has the length of 1/60th of a second, hence there are 60 ticks in a second and 3600 ticks in a minute.
- ↑ Information taken from the
Desktop 1.4.4.9 source code, method
UpdateInvasion()
inTerraria.Main.cs
. - ↑ Information taken from the
Desktop 1.4.4.9 source code, method
StartInvasion()
inTerraria.Main.cs
. - ↑ Information taken from the
Desktop 1.4.4.9 source code, methods
DrawInvasionProgress()
inTerraria.Main.cs
andCheckInvasionProgressDisplay()
inTerraria.Main.cs
. The actual condition is a 312.5×312.5-tile rectangular area centered on the enemy intersects with a 72×54-tile rectangular area with its top left corner at the tile at top left corner of the screen.