Mysteries of the You-niverse is a Season 2 episode.
Kitty, Dudley, and The Chief fight over Keswick on his Birthday, but all that changes when Keswick is captured by Snaptrap and sent to a different earth---Our Earth! What will the humans think when they see an animal from another universe?! Will they either freak out or be surprised when they see an animal they've never seen before called a Kezwick that goes through a metamorphosis!? Will they do a bunch of tests on him?
- This is the first time the character are seen as real animals.
- First and only time humans are seen. (Not counting Hot Dog)
- Both our planet and this show's planet are named "Earth".
- Even though the animals of T.U.F.F. Puppy live like humans, they don't know what humans are.