Seriously, even for wildlife lovers who believe everything out there happens for natural reasons - this video is the stuff of nightmares. If you're of a sensitive disposition it's probably best to leave this page now.
Still with us? OK.
The video shows a giant red leech - it's a newly discovered species and doesn't have an official name yet - sniffing out a worm more than twice its size before devouring it like spaghetti.
"It was either searching for an end to grab, or was working out whether it was too big to eat," said documentary director Paul Williams.
"When it found an end it started to suck. It was incredible."