What is Krabby Patty made of?

It's supposed to be made of plankton... Plankton finally gets the secret recipe and all it says is plankton and that's why all the fish enjoy it.

Wasn't that revealed to be a joke

I read a theory once that it was made of whales and that mr krabs couldn’t bring himself to kill baby Pearl when he was hunting for whale and found her

His skin was pale and his eye was odd