If you happen to go swimming in Papua New Guinea, you might want to wear a cup. Locals there say a certain type of fish has killed at least two men by -- wait for it -- chewing off their testicles.

Unlike a piranha, the Pacu Fish, otherwise known as the "Ball Cutter" (no, really), doesn't have an underbite, so its teeth have a creepily human-like appearance. In addition, it can grow to be as large as 60 pounds, and apparently tears off the testicles of unwitting fishermen and swimmers, leaving them to bleed to death.

The Ball Cutter's diet normally consists of seeds and nuts (the other kind), but apparently it has a rather broad definition of the latter. Why it considers guys' dangly bits to be such a delicacy is still unknown -- but such meandering thoughts probably didn't occur to the victims, who likely just wondered if a scorned ex-girlfriend had taken up snorkeling.

If all that wasn't enough to give you nightmares, take a look at a Pacu Fish on the Animal Planet series 'River Monsters.'

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