Fortnite has had a ton of Limited Time Modes (LTMs), but a recent Reddit fan concept has received a lot of attention.
This proposed mode, titled Kevin's Curse, was posted to the Fortnite subreddit today by u/powercastle1000. The mode's name comes from the famous Cube that appeared in Fortnite in Aug. 2018. The Cube got its name because in the Fortnite subreddit's mega thread concerning its appearance, the word "cube" was banned so players started referring to it as Kevin. The name stuck.
The proposed Kevin's Curse LTM would be a Halloween event available to duos and squads. One feature of the LTM would be that all water would have the purple bouncy effect. The storm would tick for more, but would also be low gravity. Keeping to the purple theme, all loot would be purple. Loot would include some, but not all, of the loot available in the Unvaulted LTM. Loot is "Vaulted" when it is removed from the game, but the Unvaulted LTM event allowed players to use previously-removed loot.
Epic Games keeps involved with the Fortnite community. If u/powercastle1000's proposed LTM picks up enough steam perhaps we could see it come to Fortnite this Halloween season.