Super Dimentio is the insane fusion of Dimentio and Luigi after brainwashing him back into Mr. L. It results Dimentio being nearly as strong as Thanos. He was destroyed by Ronald McDonald, forcing Dimentio to flee and Luigi being restored.
It was at first a puppet before Dimentio went inside its head to control its mind and actions. When Dimentio is not controlling it, it acts zombie-like, specifically when it says "GREEEEEEEEEEEN" and "L-POWER!".