R.E.V.E.N.G.E. Robot

The R.E.V.E.N.G.E. Robot appears exclusively in A Big Red Barn, and was created when all the revenge that had been vowed in the universe came together to form his metally goodness.

A Big Red Barn
The R.E.V.E.N.G.E. Robot was created after an excess of characters vowed revenge on other characters, causing the Robot to be formed. He was originally housed inside a 6-story laser tag facility, but as more characters vowed revenge, he eventually grew through the laser-tag building, out of the earth, and at one point occupied most of the known universe. After a prompt paradox and un-paradox, he was changed into the REVENGE Robot, and proceeded to draw revenge vows from many more Funonzi characters.

Anatomy
The R.E.V.E.N.G.E. Robot's anatomy consists of metal plating that covers all its inner workings, so nobody really knows how it functions. However, one oddity of the robot is that, though his body grows with the amount of revenge being vowed, his head stays exactly the same size no matter what.