The Arroool planet was an otherwise unnamed class M planet located at the the galaxy's frontier in the Alpha or Beta Quadrants.
History and specifics[]
In 2274, the Federation starship USS Enterprise orbited the world to observe an impending extinction-level event, as it was about to be struck by a 20-mile-long asteroid. A landing party visited the surface two hours prior to impact, finding it populated by a herd of large, peaceful animals that made "arrool" howling noises. The herd gathered in a valley and through telekinesis deflected the asteroid. (TOS - Untold Voyages comic: "Worlds Collide")