Fake Missy

Fake Missy shows up as a knowing wink at Big Mouth's own history, a version of Missy voiced by Jenny Slate who appears just long enough to acknowledge, out loud, that she isn't the 'real' Missy anymore. She's chatty, self-deprecating, and treats the whole situation as material rather than a wound.

It's a rare bit of a show turning its own real-world casting controversy into a joke without flinching from it, and Slate leans into the absurdity with total commitment rather than defensiveness. The bit works because it trusts the audience to know the context and rewards them with candor instead of evasion.