Johnny Bravo (1997)

S2E19 I, Fly

While keeping an eye on Carl's science project, Johnny inadvertently transforms into a fly. Now, he navigates life with a human head atop a fly's body, while the fly inhabits Johnny's human form, sporting a fly's head. Caught in this bizarre swap, both must adapt to their new realities and find a way to reverse the mishap before it's too late.