The caterpillar zombies are coming!

Think that zombies are just fiction? Not for caterpillars, it isn’t: there’s actually a virus that can turn healthy caterpillars into zombies.

The biology of the disease is quite fascinating as researchers found that all the virus had to do is modify a single gene in the caterpillar’s genome to turn it into a zombie..

“When gypsy moth caterpillars are healthy and happy, they go up into the trees at night to feed on leaves, and then climb back down in the morning to hide [in bark crevices or soil] from predators during the day,” said study co-author Kelli Hoover, an entomologist at Penn State University.

But caterpillars infected with a baculovirus—a type of virus that infects invertebrates—are driven to the treetops and reprogrammed to stay there until they meet a doom worthy of a horror film.

“When they are infected, as they get sicker they stay up in the trees and die up there,” Hoover explained.

The virus “ends up using just about all of the caterpillar to make more virus, and there are other genes in the virus that then make the caterpillar melt. So it becomes a pool of millions of virus particles that end up dropping onto the foliage below where it can infect other moths that eat those leaves.”