This is the unbelievable moment when a bio-researcher cuts open a euthanised 18-foot python and finds a whole 5-foot alligator swallowed inside.

The Burmese python (Python molurus bivittatus) was discovered by a group of field workers in the Florida Everglades, in the USA and was later euthanised and handed over to a research lab.

The species is one of the largest snakes in the world and can reach more than 20 feet in size.

Social media creator Rosie Moore, 26, who is also a geoscientist, had the opportunity to study the gigantic serpent, which was roughly 18 feet in length.

But what was even more amazing was the fact that inside the enormous creature’s stomach was a five-foot-long alligator.

In this footage Newsflash obtained from Rosie, researchers can be seen examining the snake’s clearly swollen stomach eagerly waiting to find out what its last meal was.

And after only having cut away its thick skin – the scientists could clearly see a giant gator that the python swallowed whole.

In a caption below the video, Rosie explained: “Due to the subtropical environment of South Florida, paired with the Burmese pythons’ long life span and rapid reproduction, these snakes have successfully invaded ecologically sensitive areas such as Everglades National Park.

“This poses a threat to a variety of wildlife, due to the pythons’ wide dietary preferences,” she added.