If you happen to go swimming in Illinois' Lake Lou Yaeger anytime soon, you might want to check your nuts—literally. In response to a report that a fisherman had found a piranha last month, lake superintendent Jim Caldwell took an intimidatingly-toothed fish to the Illinois Department of Natural Resources, where it was identified as a pacu.

Pacu hail from the Amazon Basin, have human-like teeth, and can weigh up to 55 pounds. Worse, they appear to have a taste for nuts, and yes, we mean those nuts. British fisherman Jeremy Wade says two men died of blood loss in 2011 after having their testicles bitten off by pacu. This earned them the name "ball cutter."

Caldwell continues to swim in the lake every day, saying that pacus pose no threat to humans because they typically eat snails, aquatic vegetation, and non-human nuts. Is it really worth the risk, though?

[via The Huffington Post]