The Slime Rain event starts when the message "Slime is falling from the sky!" is displayed. During the event, Green Slimes, Blue Slimes, and Purple Slimes, along with the occasional Pinky will rain down from the sky. After a total of 150 slimes have been defeated, (or 75 if King Slime has been defeated previously), the King Slime will spawn. The event ends shortly after King Slime is defeated. If King Slime is not defeated after so much time has elapsed (9-15 in-game hours) the event will end prematurely. When the event ends, a message will appear saying "Slime has stopped falling from the sky".
- This event can be a good grind for new players since they can get a lot of Gel for torches and be able to get Slime Hook or Slimy Saddle easily if they can defeat King Slime at the end.
- If played in Expert Mode, it is possible for Slime Rain to occur before the criteria are met, although the chances of this happening are significantly lower.
- If King Slime hasn't been defeated in the world yet, the odds of a Slime Rain occurring are doubled.
- The Slime Rain event can also cross with other events and boss fights, such as the Goblin Army event or the Eye of Cthulhu boss.
- The event can be avoided by staying underground until it ends.
- If the player saves and exits the game, the Slime Rain event will be re-triggered the next time the world is loaded, effectively resetting the time on the event.
- The Slime Rain is the only event that does not change the music.
- If the players goes high enough, the Slime Rain effect can be seen in the background before the event is announced.
- Added to the game.