Whenever hailed it throws a snowball at its greeter. Otherwise it just follows you around, the definition of a fluff pet. It overrides other fluff pets when summoned but not the deity pet. When it is up you may be able to summon a second fluff pet (depends on the pet). It was added in 2011. Reward from the quest "A Frostfell Favor" in Frostfell Wonderland Village.