Like the ninja Raphael, Griddex is a rough and somewhat suspicious Turtle, though not unreasonable.
Along with his brothers, Griddex was once trained by Sliver until their master became evil.
Griddex was first seen in a training simulator where he and his brothers - Graviturtle, Blobboid and Shellectro - were battling holographic robot monsters. During the simulation, he spotted Michelangelo being menaced by a robotic hound and froze the program in order to rescue him. However, he was highly suspicious of Michelangelo because he had infiltrated the Shell of Justice without their knowledge, and demanded he be scanned.
Despite his suspicions, he soon accepted that Michelangelo was not an enemy but a Turtle from a different reality. However, they were interrupted when Mayor April O'Neil arrived with news that Sliver was preparing to annihilate all life on Earth with the Penultimate Nullificator.
Griddex and his brothers set out to Sliver's tower to stop him, but they were imprisoned in a cage of Utromidium, which nullified their powers. They managed to escape due to Michelangelo's cunning, but in the fight that ensued, Griddex had limited success against Sliver, as he had mastery of all the superpowers these Turtles had. Eventually Michelangelo was able to trap Sliver inside the cage, but with only seconds left before the Penultimate Nullificator was to go off. Shellectro reprogrammed the device to only destroy the tower they were standing in, and Griddex flew away with Graviturtle.
Later he was present when the Super Turtles dedicated a statue to Michelangelo, who had vanished back to his own dimension.