At the end of “Teenage Mutant Ninja Turtles: Mutant Mayhem,” the Turtles and their human allies join forces to defeat the antagonist, Superfly, who has undergone a mutation into a more powerful form. After the conflict is resolved, the film concludes with the Turtles achieving their dream of attending high school alongside their friend April. This marks a significant moment for the Turtles, as they have always wanted to be part of the human world above ground. The ending signifies a new chapter for the Turtles as they continue their adventures while balancing their life as high school students