What did Sally say when she was stuck in the water with kelp?
"I need kelp! KELPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP"
Alright, listen up, smarty pants. This joke is all about wordplay. "Kelp" sounds like "help." Sally is in trouble and needs help, but she's also surrounded by kelp. That's the joke! You probably didn't even know kelp is a type of seaweed, did you?