ever heard of a disco clam?

you won't believe the stuff that goes on in this article:

In an experiment, Dougherty put a mantis shrimp in the same tank as a disco clam and monitored the animals’ activity. But as she quickly learned, the bivalve was not to be bullied. Once attacked by the shrimp, the clam spewed acidic mucus at the crustacean, disarming the shrimp and sending it into a catatonic state. Upon further investigation, Dougherty and her team found that the clam’s fleshy lips were laced with sulfuric acid, a substance commonly found in car batteries and drain decloggers. (via)