The Freeze

A mob similar to the Blaze and Breeze, however ice-themed for the ice caves of course :). The Freeze would glide over the ground as it moves and has a super cold-aura that causes all entities nearby to get the freezing effect (or freezing ticks). It emits or whirls up the cold around itself to keep its temperature and slow opponents. Instead of fire balls or wind charges it could shoot the ice balls.
It would/could drop ice rods/freeze rods that could be used to craft ice balls or create chilled ice blocks (that create freezing water around them) or some other use.