A shark was swimming through the ocean when he spotted a squid floating there looking rather sorry for itself. He swam up to the squid and enquired as to what was ailing it, to which the squid responded that he reckoned he'd eaten some dodgy shellfish or something and he felt like absolute shit. So the shark said "well hop on my back and I'll take you home".
A little while later, as the shark was swimming along with the squid on his back, he bumped into his mate the killer whale. "Alright mate?" said the killer whale. "Yes, not bad ta chief", responded the shark. "Oh, by the way, here's that sick squid I owe you."