my favourite pokemon is espeon

So I'm playing in a warm ocean-only world just for funsies, which means I don't have most of the typical mob selection. I'm looking at tutorials for infested potion-based EXP farms, which seem pretty easy, but the caveat is they all require an armadillo.

I do not have armadillos.

So I hop into a test world to figure out if I can make a similar contraption using only the mobs I have access to, and I stumble on a funny little mechanic.

So witches have predictable behaviour, and will consistently throw potions of poison at any entity that is 1) not poisoned 2) closer than 8 blocks away and 3) has more than 8 hearts.

And chambered nautilus is immune to poison.

So by accidentally aggro'ing a nautilus onto a witch while trapped together in a little bath tub, they are stuck in an eternal loop of the witch poisoning only itself, getting rammed by the nautilus, and then drinking heal pots. No one ever dies.