This is Buddy. I got him from a Menagerist Goblin, but cannot remember exactly when. Diablo Wiki says that Buddy was added in patch 2.4.1. The Diablo III website says that Patch 2.4.1 went live on April 26, 2016.
The flavor text for this pet says: His favorite game is “Fetch the Skull,” but try to make sure no one is using the skull first.