Contrived Coincidence: When Donnie introduces Casey to Metalhead, he thinks Donnie made a "little robot Raph." While Donnie corrects him that he made Metalhead before Raph's mutation, he does acknowledge how weirdly similar his design is to a post-mutation Raphael.
Cutaway Gag: After Metalhead discovers the portal in the porta-potty, a random girl in South Carolina browses Wikipedia and finds this fact on the page for Porta-Potty.
Spared by the Adaptation: It was at this point in the original series that Metalhead was destroyed saving the various kidnapped mutants. Here he makes it home intact.
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