Courage, le chien froussard s04e20
Titre original : Courageous Cure
Two multi-armed aliens come to Earth to find an antidote for a disease that makes everyone on their planet beat each other up with their arms. They expriment on Eustace and Muriel, only to find they don't have the antibodies to get the cure. Courage had the cure in him the whole time, and the aliens get it.