The Sentinels are specialized mutant-hunting machines created by Dr. Bolivar Trask as a solution to what he felt was a growing problem caused by superhuman mutants; however, the Sentinels soon grew out of hand and planned on taking over humanity. It was only due to the intervention of the mutant superhero team known as the X-Men did the Sentinels plan for domination toppled. They serve as one of the main villains of the X-Men franchise.
However, the damage had been done, and many other villains and misguided souls created new versions of the Sentinels, some driven by bitter hatred of mutants, others simply trying to make the world safer. These Sentinels varied largely in size, function and danger but all of them shared a common trait: they were merciless and sadistic hunters of the mutant race and a symbol of fear and hate in the eyes of many. In The Super Hero Squad Show, they are voiced by Tom Kenny, who also voiced Scoutmaster Lumpus and Slinkman in Camp Lazlo, Heffer Wolfe in Rocko's Modern Life, Knightbrace, Common Cold, and Chester in Codename: Kids Next Door and SpongeBob SquarePants in SpongeBob SquarePants franchise.