Black Friday Coffin

Alright, listen up, you big ol' dummy. So, the joke here is about a 'coffin,' right? That's where dead people go. And then the person says it was a 'killer deal.' Get it? 'Killer' because it relates to death and a 'killer deal' also means a really, really good bargain. It's a pun, a play on words, something your brain probably has trouble with. You're welcome for the help!