Tar beast

Tar beasts are bog beast-like elementals that live around the Lakkari Tar Pits in Un'Goro Crater.

Tara plans to get rich by creating glue from super-sticky tar, and asks adventurers to help her by scraping the substance from tar beast corpses.

In Hearthstone
Three tar beasts (Tar Creeper, Tar Lurker, and Tar Lord) appear in the Journey to Un'Goro expansion for Hearthstone. They each share a common theme as Taunt minions with poor attack during your turn but increased attack during your opponent's. Notably, they're depicted as elementals constructed from tar rather than bog beast-like creatures.

In the RPG
A tar beast is a mud elemental, made of water and earth. It is a creature draped with green moss and oozes in order to move across the ground. Its hide appears slick, taut, and rubbery, and the creature forms and retracts small pseudopods as it moves. Any face it might possess is hidden under the moss.

In the steamy bowl of the Un'Goro Crater, the enigmatic tar beasts rise from bubbling black pits to destroy those who cross them. Also found in warm swamps, tar beasts are primal elementals born of the land. Few travelers ever see a tar beast unless they somehow anger the monster — in which case they feel the unbridled wrath of the elemental. As tar beasts are quiet, reclusive, and unspeaking, no one quite knows what will anger one.

Some scholars theorize that primal forces of nature inhabit and animate tar beasts. The fact that such creatures almost always form in extremely ancient, primitive locations bears this theory out, though it certainly proves little. Others claim that the spirits of deceased dinosaurs, trapped and drowned in the tar pits, animate these elementals. The tar creatures seem to understand Common and Kalimag (which seems to indicate that they may not be dinosaur spirits), but they don't speak.

Tar beasts begin combat by hurling blobs at their nearest foes. When an enemy closes in, the tar beast engages that enemy only until it becomes stuck in the tar creature's adhesive skin. The tar beast then shifts its focus to the next-closest enemy.