Like a plot from a horror film, there’s a virus that brainwashes caterpillars, forces them to march up trees, then turns them to goo.

Now scientists at Penn State University have found the single gene that enables the virus to carry out its dark deeds.

The caterpillars would normally return to the ground to hide after feeding on leaves, but the baculovirus reprogrammes them to stay in the trees, melts them, then drips down among the remains to infect more of the creatures.