The pacu, a non-native toothy fish found in Illinois' Lake Lou Yaeger recently, can weigh up to 55 pounds and is known to eat nuts ... in more ways than one.
Responding to a report that a fisherman had reeled in a piranha there June 7, officials identified as a pacu. Another pacu was seen a couple of weeks later.
Pacus primarily eat nuts, aquatic vegetation and snails, wildlife experts told KDSK, and pose no real threat to humans ... well, most of the time at least.
Residents of Papua New Guinea may beg to differ.
There, according to British fisherman Jeremy Wade, the pacu is known as the "ball cutter" because ... well you can probably figure that one out, right?
In 2011, Wade said locals informed him that two fisherman had died from blood loss after something in the water had bitten off their testicles. Ouch.
"The locals told me that this thing was like a human in the water, biting at the testicles of fishermen," Wade said, noting that such attacks are uncommon.
One can only hope.