Polar bear (Beast)
Grimclaw is a level 13 polar bear found in Darkshore. To be precise, he is located by the main north-south road, just a short distance south of the fork where you walk off to the Grove of the Ancients, on the left hand side of the road if you are facing south.
He plays a part in by pointing in the direction towards his master, Volcor, when you wave at him (by typing "/wave" when he looks at you). He is introduced to you in the quest where he signals Volcor's danger to Terenthis.
This section concerns content exclusive to Cataclysm.
In World of Warcraft: Cataclysm, Grimclaw was sent by Volcor ahead of Auberdine's destruction and is badly injured by poachers. Keeper Karithus and Seraphine watch over the injured bear and task you with seeking out various remedies, before he can be safely moved to Lor'danel. After receiving treatment phased content shows Grimclaw in Lor'danel, where you learn that Volcor has just died from his injuries.
In a later phase, Grimclaw has decided to associate himself as the companion of Cerellean Whiteclaw, who finds more comfort with the bear's presence than he would have first thought.