catpat
MatPat and his wife Steph's cat! His name is Skip but us theorists tend to call him CatPat. If you watch MatPat's live streams (GTLive) he'll often pop up rIGHT IN FRONT OF THE CAMERA.
Steph: Hi skiiiiip!
Jason: Everyone look! It's CatPat!
Jason: Everyone look! It's CatPat!