Stomach-churning footage shows a caterpillar sprouting dozens of writhing maggots which took control of its body.
In the video, the parasitic maggots emerge from the insect's body while it was supposed to go into a chrysalis.
Shocked insect enthusiast Penny Pen said she recorded the caterpillar in her garden in Nottingham UK on June 30 and gave them fresh nettles as she expected them to pupate anytime soon.
Most of the caterpillars had started shedding a few hours later except for the one with the maggots.
Penny said: "Unfortunately, in panic, my husband said it was awful and that I should perhaps put the poor caterpillar out of its misery. Without having any other advice or knowledge, I buried it quickly thinking of the poor caterpillar."
The caterpillar appeared be suffering from parasitic wasps that had laid eggs inside its body.