Two whales were swimming around in the ocean (as whales do), when they come upon a ship that has a cargo of potatoes.
The first whale swims underneath the ship, tips it over and eats everything, ship and all.
A few days later, the two whales are still swimming around in the ocean when they come up to another ship that is loaded with potatoes.
The first whale capsizes that one, too, and eats everything on board.
The third ship they spot is also hauling potatoes, and once more the first the whale upends it and eats everything on board.
“Why do you keep tipping over those ships full of potatoes and eating everything on board?” the other whale asks.
“I wish I hadn’t done it,” the first whale says, “but I just can’t help myself once I start. You know how it is — you can’t eat just one potato ship.”
Sorry – I know it’s a really bad joke, but I couldn’t help myself!
Image used under a Collective Commons License from: https://en.wikipedia.org/wiki/Sperm_whale#/media/File:Mother_and_baby_sperm_whale.jpg