Rainbow Head is one of the Cosmetic features on Minecraft Central. It was added on the 1st of April 2016 and belongs to the category Lobby Gadgets. It only works in the Lobbies. There is a cooldown of 30 seconds between the uses of this gadget. When used, the gadget places a wool block onto the player's head that changes colour and shoots wool blocks around the player.
The only way to obtain this feature is by getting it from the Voting Villager. Previously, before the 20th of May 2021, it was available from Cosmetic Treasure. The gadget can be enabled in Lobbies through the Lobby Collectibles menu.