Rumble McSkirmish

Rumble Mc Skirmish is a fictional fighting videogame character in Gravity Falls that he was brought to life by Dipper Pines by inputting a secret code in an arcade. Though shocked at first, he saw this as an opportunity to have a chance in the fight he had gotten into with his love rival, Robbie. It turns back on him when the only reason that sets Rumble off (and quite possibly the only one he seems to understand due to his programming limitations) is that Robbie had killed Dipper's father, which sets the pixellated fighter on a rampage, in pursue of Robbie until he can "Finish him".