Janna Clinton was sitting on her back porch watching her son Charlie, 11, fish in a pond behind their house in Oklahoma this past weekend when he suddenly started yelling for her.

"He was screaming, 'Oh my God, mom! Oh my God!' " Clinton told NPR.

"I thought he was just being dramatic, to be honest," she added.

Then she got a close look at Charlie's alarmingly weird catch.

"Obviously being in a neighborhood pond, we're used to just catching a few bass or catfish," she said. "I mean, nothing with human-like teeth."

It turned out that Charlie had landed a pacu, a fish that's a cousin of the piranha — and whose outsized teeth have long struck fear in swimmers. The pacu is a native of South America, but this one was swimming in a small pond in the Clintons' suburb north of Oklahoma City.

"He said it put up a heck of a fight," Janna told NPR, saying her son reeled the fish in on his own. "He was the only one down there fishing and he did a great job."

The pacu was released back into the water

The Clintons posted a photo of the unusual fish to their neighborhood Facebook page and got in touch with a game warden. But before learning of its provenance, they returned the pacu to the water.

"It's a catch and release pond," Janna said, "so we unfortunately did release it back because we didn't know any better at the time."

People who later recognized the fish said it was invasive and shouldn't be released, she said, adding, "We made a mistake there."

Since then, Charlie has been stalking the fish.

"He did stay at the ponds pretty late that night trying to catch it again," Janna said, adding that her son has been rising early and staying at the pond late, hoping to get another bite from that pacu.

If Charlie succeeds, a neighbor has offered to eat the pacu. But Janna Clinton has other ideas.

"If he catches it again, we're going to get it mounted for him. I think that's a heck of a prize and he deserves it," she said. "I told him we'd make it look like the fish was smiling so you could see its teeth."

The wildlife agency blames a pet owner for the pacu's presence

Game wardens believe the pacu was a pet that outgrew its tank and was released into the wild.

"How dare you," the Oklahoma Department of Wildlife Conservation said, addressing the fish's previous owner via Twitter and setting off a lively exchange with surprised members of the public.

"WHY DOES IT HAVE HUMAN TEETH," a dismayed commenter asked. "IDK WE DIDN'T MAKE THEM," the wildlife agency replied.

When asked what kind of bait Charlie used to entice the pacu to bite, his mother said, "You're going to laugh. It was just a piece of bread."

Pacu have been found in Oklahoma before

Not only is this not the first pacu caught in Oklahoma — it's not the first time one's been hooked by an 11-year-old in the state. Charlie follows in the footsteps of Kennedy Smith of Lindsay, Okla., who caught a pacu five years ago.

"These fish are generally harmless to humans, but the practice of dumping unwanted pets in waterways can be incredibly harmful to native wildlife," the wildlife agency said via Facebook. It warned that pacu can grow to sizes up to 3.5 feet and 88 pounds.

As for whether the invasive pacu is becoming more common in Oklahoma, Kelly Adams, a communication and education supervisor at the agency, told NPR, "This is not an increasing trend. I'd say every couple of years we get a report."

Anyone who catches a pacu should keep the fish and contact a game warden, Adams said.

The fish also has a scary nickname

Along with its creepy appearance, the pacu has a troubling nickname: "the ball cutter," a label that stems from its purported habit of attacking men's testicles. That dubious distinction prompted warnings for skinny-dippers in Scandinavia after one of the fish was caught in the wild in 2013.

"It's not normal to get your testicles bitten off, of course, but it can happen, especially now in Sweden," fish expert Henrik Carl said at the time, although he warned that people were still more likely to die from drowning than from a pacu attack.

In reality, the red-bellied pacu and related species actually rely on nuts and seeds from fruit trees and plants as a main food source, according to Animal Diversity Web, a project by the University of Michigan's school of zoology. Still, the animals are omnivores — and their appetite grows with their size.

Charlie Clinton, 11, holds the pacu he caught. Game wardens believe the fish was a pet that outgrew its tank and was released into the wild.