A stack of crates rises from the floor, holding up one child and exciting another. The boy on the crates stands silently while the other questions aloud “aren’t you going to stop us from doing the milk crate challenge?”
A woman in a towel, holding a cup, passively watches the pair, slowly and deliberately takes a sip, and finally lowers her cup again, before simply replying “nope.”
Just so you don’t get left hanging. I don’t think it’s a real thing. Just kids doing a dumb, dangerous act, and calling it a challenge. You can see in the comic that the crates are uneven, so this qualifies