Researchers in Broward County, Florida are trying to keep the iguana population under control by bashing them in the head.

Fifteen researchers from the University of Floria are using “blunt force trauma” to destroy the iguana’s brain and “humanely” kill the invasive reptile.

The work is apparently complies with the state’s anti-cruelty laws, if it is done with one strike.

The researchers have been hunting down invasive iguanas with captive bolt guns as part of a three-month, $63,000 research project.

Contracted by the Florida Fish and Wildlife Conservation Commission, the project aims to remove the rampant reptiles and runs until May.

“I like all creatures, but they are not in their native environment,” Floridian Eric Swalley tells media. “It’s a horrible thing we need to combat and try to get a handle on. It’s a biological nightmare.”

It’s legal to kill iguanas in Florida because they can destroy native plants and wildlife.

But state law dictates the killing must only be in a humane manner.

“Most of what we’re doing is blunt-force trauma,” said UF Jenny Ketterlin biologist told the South Florida Sun Sentinel. “Hitting their head very hard against a solid object.”

Experts recommended other ways to kill them such as shooting them with a pellet gun, or decapitating them with a knife.

Although freezing the animals was once allowed, it’s now illegal, along with drowning and poisoning.

So far the teams have killed nearly 300 iguanas.