Stuffed creature of indeterminate species is a prize in the ball toss game at the Mystery Fair.
In "The Time Traveler's Pig," Wendy asks Dipper to win her one of the creatures of indeterminable species. The ball bounces back and accidentally hits Wendy in the face, giving her a black eye. Robbie then comes up and takes his snow cone and uses it as an ice pack on Wendy's eye when he asked her to be his girlfriend. Dipper repetitively attempts to change the timeline and only successfully avoids hitting Wendy and winning the creature once.
A Stuffed creature of indeterminate species is a light purple bear-like creature, with darker purple spots around its eyes and round ears like a panda, blue arms with sharp claws, a duck-like bill and webbed feet, and a blue bit of fuzz on top of its head.
- 109. "The Time Traveler's Pig"