What is the name of the dog-like creature that befriends Jake Chambers and follows the group through their journey?

The dog-like creature that befriends Jake Chambers and follows the group is Oy, the Billy Bumbler. In Stephen King’s The Dark Tower series, Oy is an unusually intelligent billy-bumbler from Mid-World who joins Roland Deschain’s ka-tet after Jake encounters him in The Waste Lands.

Oy resembles a cross between a dog, raccoon, and badger, with distinctive gold-ringed eyes and the ability to imitate human speech. He becomes especially devoted to Jake, providing companionship and comfort throughout the journey. “Oy” is the canonical name, while “Billy Bumbler” identifies his species, so the stored answer is fully acceptable.