Scientists have discovered a species of ant that, well, lies terrifyingly in wait for its enemies before tearing them apart limb by limb.

Called Azteca brevis, the ants were found in Costa Rica’s Piedras Blancas National Park in 1999. But it was only when observed more closely that their alarming traits became apparent. A study describing the findings is published in the Biological Journal of the Linnean Society.

“The finding was in fact very surprising,” Markus Schmidt from Biofaction in Austria, one of the study’s authors, told IFLScience. “It was indeed so surprising that my research colleagues went to the forest to repeat the experiment before they fully believed it. But that is the hallmark of science, any finding should be able to be replicated by others!”

The ants lie in wait in holes on the branch of a plant, big enough for their mouths (mandibles) to fit through. When prey up to 50 times bigger than an individual ant lands on the branch, the team of ants strikes, simultaneously biting down on the prey and dragging it into the holes. Over the course of 20 minutes to several hours, they will tear the prey apart.

“They seize the extremities of these arthropods and pull backwards, immobilizing the prey, which is then spreadeagled and later carved up or pulled into a gallery before being carved up,” the study’s authors, the other being Alain Dejean from the University of Toulouse in France, wrote in their paper.

New Scientist described the process as a “medieval torture rack”, as the ants stretch and tear their prey apart, including grasshoppers and leafcutter ants, and carve it up on the spot. Ew.

This trait, while unusual, has been seen in another species of ant – Allomerus decemarticulatus – described back in 2005. They employed a similar technique, although they were rather more ambitious, seeking prey up to 1,800 times heavier than the average ant. And they seem to be the only two ant species that do this.

“Last time I checked there no other ants who build traps, neither this way or any other way,” said Schmidt. “We suspect the reason for these plant-ants to develop this strategy is the lack of proteins in the diet of arboreal ants, since the ambush technique is presumably a very energy efficient way to prey on (larger) insects.”

Ants, basically, are frickin’ crazy. Don’t cross them.

[H/T: New Scientist]