Snow imps were part of the 2007 and 2016 Christmas event. They gave away hats and weapons for snowmen, and teleported players to the Land of Snow or back to RuneScape. Unlike regular imps, they could not harm players, nor could players attack them.
The hats given by the snow imps included pirate hats, top hats, barbarian hats, dragon hats and dwarf hats, which could be put on their snowman, temporarily giving life to them, enabling the player to talk to them. They would also give the player snowman weapons. The player could get a Holly Bow, Winter Staff or Ice Sword. These would make the players snowman jump to life and start fighting other snowmen. However, the player could not take these out of the Land of Snow.
In the 2016 event, due to being on strike, they refused to give away any snowman hats or weapons.
The update history project is a work-in-progress – not all updates to this topic may be covered below. See here for how to help out!