|The Martian Probe before spotting the player (left) and after (right). If the Probe is able to escape after detecting the player, the event begins.|
|Progress bar icon|
Martian Madness is triggered by a Martian Probe, which spawns randomly in the two outer lateral thirds of the map (with a higher spawn chance in the Space layer). When this small flying enemy detects a player or is attacked, it immediately attempts to fly away. If the Probe escapes, the event starts. This requires at least one player with at least 200 maximum health to be in the world – otherwise, the event will not start.
Once triggered, the status message "Martians are invading!" appears, and UFOs start flying in the background (as seen in the banner above); though Martian Madness enemies will not actually begin spawning until the player is located near the default spawn point or near an NPC with valid housing. As with other invasion-style events, a progress bar is shown in the bottom right corner while the event is ongoing. This bar fills as event enemies are defeated. When it reaches 100%, the event ends and Martian enemies stop spawning.
- A Martian Probe will not spawn if the Lunar Events are active, or if a Martian Madness event is already started, or if another Martian Probe is currently already present anywhere in the world.
- After exiting a world during a Martian Madness event, the screen in the main menu will still have Martian probes flying around.
- Playing in Expert Mode does not increase the drop rate of Martian Madness items, but it does increase the spawn rate of the Martian Probe.
- Exiting the world just before the Probe despawns may prevent the event from occurring when it is re-entered.
- Martian Saucers are much more common after 50% of the event has been completed.
- Martian Madness is one of the more difficult events to have occur, due to the fact that its summoning requires a random spawn of a Martian Probe. However, with a proper spawn platform or via the use of a Floating Island towards the outer thirds of the map, it can be "summoned" more easily.
- If the Martian Probe has detected a player, chasing it might cause it to despawn, thus care should be taken.
- While most minions will not deliberately target the Martian Probe, some can still accidentally kill it before it has the chance to detect players and escape, preventing the event from triggering. Minions should be dismissed if the player is trying to cause an invasion to occur.
- Since the Martian Saucers drop the most valuable loot out of all enemies, it is usually preferable to allow as many of them to spawn as possible. Moving to a small arena high enough above the ground makes it easier to ensure no ground-based enemies spawn, increasing the chance of a Saucer to spawn.
- Unlike most other enemies in Terraria, Martians have purple blood when killed rather than red.
- Martian Madness is one of only two invasion-style events that cannot be manually started by the player, the other being Slime Rain.
- The name of the event could be a cultural reference to a real-world American basketball event known colloquially as March Madness.
- Desktop 126.96.36.199:
- Added the alternative Martian Madness music, originally from Terraria: Otherworld, which plays once the player has entered the 05162020 seed and pressed the "Music" option in the Party Girl's menu.
- Added Master Mode-exclusive drops from the Martian Saucer, including the Martian Saucer Relic which always drops and the Cosmic Skateboard which has a 1 in 4 (25%) chance of dropping.
- The Anti-Gravity Hook, Charged Blaster Cannon, Laser Drill now have a 1 in 800 (0.125%) chance to drop from any common Martian Madness enemy rather than the Martian Saucer. Subsequently, the other items dropped by the Martian Saucer now each now have an increased chance of dropping.
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