Easter Trick or Treat is an emote unlocked as reward from the 2016 Easter event. The reward for the 2017 Easter event, unlocked an additional emote added as an option for this emote, Human to Bunny emote.
The first emote features the Easter Bunny offering the player a chocolate egg from a basket of eggs, who takes a bite and loses a tooth due to it being a piece of coal instead. The bunny, who turns out to be Sliske, teleports away before the player is able to retaliate.
The additional emote is the transformation into a bunny before morphing back to human. It is the same animation as used in various Easter events, from 2007 onwards.