|AI Type||Head AI|
1000 (during the day)
|Defense||1010+25 per hand alive|
00+25 per hand alive (while spinning)
9999 (during the day)
|Debuff tooltip||Cannot regenerate life|
|Entering spinning phase|
|AI Type||Skeletron Hand AI|
|Debuff tooltip||Movement speed is reduced|
Skeletron is a pre-Hardmode boss. It must be defeated prior to entering the Dungeon, and defeating it grants unlimited access to all Dungeon areas for all players. It also causes the Clothier NPC to spawn, as long as a vacant house is available.
If attempting to enter the Dungeon before killing Skeletron, Dungeon Guardians spawn once a player reaches 0 depth. These enemies generally kill any player with a single hit, dealing 1000 damage. Managing to defeat a Dungeon Guardian does not grant access to the Dungeon, thus defeating Skeletron is mandatory for (safely) entering the Dungeon.
Skeletron is summoned by speaking to the Old Man at the Dungeon's entrance at night, who will turn into Skeletron when selecting the "Curse" option. If the Old Man is spoken to during the day, he will ask the player to return at night. Skeletron can only be summoned once per night, as the Old Man will not respawn until dawn. While players with less than 300 maximum health and/or less than 10 defense are deemed too weak by the Old Man to lift his curse, he still offers the option to summon Skeletron.
Skeletron can be summoned repeatedly this way until it is defeated. Once it is defeated, the Old Man's curse will be lifted and he will no longer appear. The Clothier NPC will arrive, bearing a remarkable resemblance to the Old Man. He can move in a town, as long as there is an empty house for him to live in. Skeletron can be re-summoned thereafter once the player acquires the Clothier Voodoo Doll. Equipping this accessory allows the player to kill the Clothier, which summons Skeletron at night. Killing him during the day will do nothing.
Skeletron is a large floating skull with two independent floating hands. All parts can travel through blocks, and will attempt to make contact with the player to inflict damage. Each part can be killed independently, but killing the head is all that is required to defeat Skeletron.
Skeletron alternates between two attack phases:
- The head remains above while the hands slash at the player.
- The head spins, dealing significant damage if touched, but dropping its defense by 10 (to 0 in Classic Mode) for the duration of the attack.
Skeletron switches between these two phases in a regular cycle during the entire fight, with the first phase lasting for roughly 13.33 seconds and the second phase lasting for roughly 6.67 seconds. It lets out a roar every time it enters the second phase.
If the player takes too long to kill it and dawn arrives, Skeletron will begin acting exactly as a Dungeon Guardian, performing a head spin attack with very high damage and very high defense, which will usually kill any players remaining in the vicinity quickly. Skeletron remains in this form until dying or despawning, even if players manage to avoid dying until the following dusk. Killing the Skeletron in this form still counts as defeating it.
Skeletron has additional properties in Expert Mode:
- The defense of its head is increased by 25 for each of its hands, resulting in a total defense of 60, initially. Once one hand is defeated, it drops to 35 and finally to 10 when both hands are defeated.
- During the spinning, its defense is therefore also only reduced to 50 / 25. Only with both hands defeated, it is reduced to 0 like in Classic Mode.
- Hand slashes are 50% more frequent and receive a 16% speed increase.
- Additionally, the hands return to the head faster after their attack.
- The head accelerates and moves faster when not spinning.
- Spin attack has its speed increased by 233%. Additionally it gets further increases under certain circumstances:
- 5% increased when one hand is down, and 10% when both go down.
- If the player is 9.375 tiles away or more, its speed gets multiplied by 1.1 for every 3.125 tiles above this threshold, up to 2.6× speed when at 37.5 tiles away.
- Once either of the hands are destroyed or the head's health is reduced to below 75% (6600), the head begins to shoot homing skulls at the player that despawn on contact with a solid block. It shoots one skull roughly every 1.33 seconds, and doubles the frequency to one skull roughly every 0.67 seconds once both hands are defeated. It pauses firing during its spin attack.
- Skeletron moves faster and has better AI when targeting multiple players. With this, it is able to "stun-lock" the player while spinning, able to almost instantly kill them if they are not able to escape (e.g. by using a Grappling Hook).
- Skeletron will inflict debuffs: its hands are able to inflict Slow, and the head is able to inflict Bleeding.
- The Old Man can be killed. However, this does not count as defeating the Skeletron, and he will respawn.
- The Old Man will respawn at the following dawn if players fail to defeat Skeletron.
- Killing Skeletron after the night ends will still count as defeating it, and will allow entering the Dungeon safely.
- Skeletron's defense and damage will revert to their normal figures if the player dies during the day.
- Defeating Skeletron is not necessary for game progression until Golem has been defeated. The Cultists, required for initiating the Lunar Events, will only spawn once both Golem and Skeletron have been defeated. However, skipping Skeletron in pre-Hardmode results in a lack of valuable Dungeon loot, in addition to access to the Mechanic as well as the Safe and Void Vault.
- Do not jump onto Skeletron's head too many times with the Slime Mount, as going too far away from it will cause it to despawn. Also, the low gravity in Space will make it almost impossible to get back down past it.
- Nonetheless, the Slime Mount can be a valuable tool during the combat, as well as a means to escape Skeletron's head spin attack, if one ever gets caught in it.
- Any ricocheting weapon ( such as the Water Bolt found in the Dungeon) is very useful.
- With multiple players, it is a good idea to set the spawn point near the Dungeon, so that players can simply rejoin the fight if they die.
- While Skeletron is immune to many debuffs on the Old-gen console version and Nintendo version, it is not immune to Frostburn on any version.
- Attacking the hands first is advised as destroying them both will make it very easy to dodge Skeletron for the rest of the battle.
- In Expert Mode, if the player keeps moving in different directions, most homing skulls will miss; also note that they do not travel through tiles.
- In Expert Mode, it is a good idea to use a yoyo or a flail and an overhead barrier.
- Assuming that the player is at 5′ 9½″ (1.75 m) in terms of height, Skeletron's head would be about 11′ (3.35 m) tall and 8′ (2.43 m) wide. The hands would be 10′ (3 m) tall and 7′ (2 m) across.
- At one point during game development, Skeletron Heads protected the Dungeon, but when one was killed, it would count as killing Skeletron, so the Dungeon Guardians were introduced to protect the Dungeon instead.
- Skeletron's head looks identical to the Dungeon Guardian.
- Counting the health from both its hands, Skeletron has even more health than the Expert Mode Wall of Flesh.
- Skeletron is the only boss not to have any guaranteed drops (with the exception of healing potions, a Treasure Bag if in Expert Mode and a relic if in Master Mode).
- On the Desktop version, Console version, and Mobile version, the Old Man has a health bar, but on the Old-gen console version and Nintendo version, he does not.
- In the Terraria and Edge of Space crossover teaser, Skeletron turns into a boss called Omegatron.
- The name Skeletron is similar to the name Skeletor, the main antagonist of the Masters of the Universe franchise.
- Blood emits from the joints between Skeletron's arms and head, possibly implying that they are severed. Going based on lore, it is guaranteed that it is the case.
- On the Desktop version, Console version, and Mobile version, a cloud in the shape of Skeletron can occasionally be seen in the background.
- In the first release of Terraria, prior to the introduction of the Wall of Flesh, Skeletron was the final boss of the game.
- It is one of the two bosses that needs a town NPC to be alive in order to be summoned. The other is the Wall of Flesh.
- The sprite file for Skeletron's arms is named
Arm_Bone. Similarly, the sprite file for Skeletron Prime's arms is named
- Skeletron is the only boss out of the three original bosses (Skeletron, Eater of Worlds, and Eye of Cthulhu) that does not have a Hardmode enemy variant (The Eater of Worlds has the World Feeder, and the Eye of Cthulhu has the Wandering Eye).
- – According to the official game lore, the Dryads ripped out part of Cthulhu's skeleton, and a curse caused all the inhabitants of the Dungeon to become undead.
- The Bestiary entry for Skeletron: "The disembodied bones of a former tyrant pulsed with a hatred so strong, it left behind a mighty curse which guards the Dungeon."
- The "former tyrant" refers to Cthulhu.
- Desktop 1.4.4: "Instant kill" attacks will no longer be avoided by Dodge procs such as Hallowed Armor or Master Ninja Gear.
- Desktop 1.4.1: No longer immune to On Fire!, Cursed Inferno, Venom, Shadowflame, Celled, or Daybroken.
- Desktop 184.108.40.206:
- Desktop 1.3.5: Sprite updated.
- Desktop 220.127.116.11: Fixed incorrect status message when summoned (was "Skeleton has awoken" instead of "Skeletron has awoken").
- Desktop 18.104.22.168: New AI and Treasure Bag added for Expert mode.
- Desktop 22.214.171.124: Skeletron now spawns on the Clothier when using a Clothier Voodoo Doll.
- Desktop 1.2:
- Can now be re-summoned with the Clothier Voodoo Doll.
- Has additional item drops. (Previously only dropped Lesser Healing Potions and money.)
- Desktop 1.0.6:
- Head health decreased from 5000 to 4400, but damage increased from 30 to 32.
- Hands health decreased from 800 to 600, defense decreased from 18 to 14, and damage decreased from 25 to 20.
- Desktop 1.0.5:
- Head health decreased from 6000 to 5000, defense decreased from 12 to 10, and damage decreased from 35 to 30.
- Hands health decreased from 1200 to 800, and damage decreased from 30 to 25.
- Desktop-Release: Introduced.
- Console-Release: Introduced.
- Switch 1.0.711.6: Introduced.
- Mobile-Release: Introduced.
- 3DS-Release: Introduced.
- Note that the player's head needs to be below 0 depth. Since the Depth Meter measures depth at the level of the player's feet, and a player is 3 tiles tall, Dungeon Guardians will only start spawning once the Depth Meter displays "3′ Underground" or more.