Left Head

Left Head is one half of a fused conjoined pair (with Right Head, voiced separately) who runs a hospital or crops up in Futurama's crowd of background weirdos, depending on the episode. Bickering, opinionated, and stuck permanently attached to a body she doesn't fully control, she treats the arrangement as a lifelong argument she never volunteered for.

The joke is structural: two heads sharing one body means every scene is a tiny domestic squabble happening mid-action, and Tress MacNeille's clipped, exasperated line readings sell the sheer indignity of it. It's a throwaway premise played completely straight, which is exactly why it lands each time she reappears.