The Koopinator is a fighter in the Glitz Pit. He is a Dark Koopatrol but has differently shaped eyes. There are only two Dark Koopatrol in Paper Mario: The Thousand-Year Door: one in the Pit of 100 Trials, and the Koopinator. He has stronger attacks than normal Koopatrol, more health, and the "dark claw attack", but he cannot call reinforcements. He is the highest-ranked member of the arena's major-league and only surpassed by the champion, Rawk Hawk himself.
Mario first encounters The Koopinator when he travels to Glitzville in search of the Gold Star in Chapter 3. When entering the arena of the Glitz Pit for the first time, Mario and his partners witness an official match between the Koopinator and Rawk Hawk. Rawk Hawk, however, manages to defeat the Dark Koopatrol without much effort, thereby defending his rank. The fight plays a key role in inspiring Mario to become a contracted fighter because the Gold Star is introduced in that scene.
- The Koopinator's name is a portmanteau of "Koopa" and "Terminator". "Terminator" is a reference to the movie of the same name.
| Glitz Pit Fighters|
|Champion:||The Great Gonzales|
|Former Champions:||Rawk Hawk · Prince Mush|
|Major League Characters:||The Koopinator · Hamma Jamma · Bamma · Flare · Craw-Daddy · Shellshock · Spiky Joe|
|Major League Teams:||Chomp Country · The Fuzz · Magikoopa Masters · Shellshockers · Poker Faces · Tiny Spinies|
|Minor League Characters:||Cleftor · Bandy Andy · Master Crash · King K. · Sir Swoop|
|Minor League Teams:||Armored Harriers · Bob-omb Squad · Punk Rocks · Hand-It-Overs · Spike Storm · Dead Bones · Pokey Triplets · KP Koopas · Goomba Bros. · Mind-Bogglers|
|Minor League Replacement Teams:||Wings of Night · Destructors|