From LEGO Batman Wiki
Yeti is a playable character in LEGO Batman: The Videogame.
A Yeti also appears in LEGO Batman: The Videogame, but here it resembles more of a white version of Killer Croc, but without the scales and blue jeans. The Yeti carries a pistol as a weapon and may be unlocked for purchase after the level Penguin's Base.
The Yeti appears on several boxes in Mr. Freeze's ice cream factory.
There is some speculation about what role the Yeti plays in the video game, some say it is one of Mr. Freeze's henchman, and others suggest that it is one of Batman's minor enemies known as "Snowman". It should be noted that the Yeti is never fought and is not unlocked after Mr. Freeze is defeated like his henchwomen are.