Frosty is an undead dragon-ling that was included with the Warth of the Lich King collector’s edition. Frosty abilities the following:

lvl1 Diseased Bite
lvl2 Call Blizzard
lvl4 Ice Tomb
lvl10 Frost Breath
lvl15 Shriek
lvl20 Blistering Cold

Many of these abilities are linked to Frost Dragons that the Lich King has in his control. Frosty would make a great Pet to have in a 3 Naxx team with Lil’ K.T. and Mr. Bigglesworth.