Grox-pas

an embarrassing or tactless insult intended to be an epic comeback;

when a try-hard intends to be funny but says something that is either lame or ill-thought

Grossly Offensive: Did you mention trash, Lizard? Are you an American now? - You're committing a grox-pas, Grossly!
Grossly Offensive: You couldn't kill anything ... because you're a pussy. - But pussies can kill. That's another grox-pas!