Get ready to have your perception of the cute little green tree frog irrevocably shattered - and it's all thanks to this old photo that led us down a rabbithole of green tree frog bastardry.

The photo shows the head of a small snake, open-mouthed, as it disappears down the gullet of an Australian green tree frog. It's been around for a few years at least, but it's seeing a viral resurgence via a reddit post in /r/WTF titled "One Last Scream Into The Abysssss."

We don't know who took the photo, or where, or when. We do know that the frog is an Australian green tree frog, or Litoria caerulea, confirmed by UNSW and Australian Museum biologist Jodi Rowley on Twitter.

One Last Scream Into The Abysssss from WTF

The snake could be a brown snake, as per this post on Google Plus from November 2016.

"This is an Australian Green Tree Frog eating a Brown Snake," the post reads.

"Previous to the capture, I had been led to believe that they ate only insects. The Australian Brown Snake is highly venomous. Although the snake had bitten the frog, as you will see if you enlarge the photo, the frog survived. Not such a happy ending for the snake however … "

The internet being what it is, and the photo apparently having been around since before November 2016, we can't be sure of the veracity of the post, but it sure looks like a brown snake.

Another possibility, Rowley said, is that it could be a juvenile keelback - brown snakes are quite venomous, and although we don't know the effect of brown snake venom on frogs, odds are good that it's not positive.

It would have to be a juvenile, though. Australian green tree frogs only grow to around 12 centimetres (5 inches) in length, while adult brown snakes average 1.5 metres (5 feet) and keelbacks grow up to 1 metre (3.2 feet).

The photo looks like it could be a cunning photo edit (and indeed has been the subject of a Photoshop battle), but it's not unknown for frogs to enjoy this sort of meal.

Green tree frogs mostly eat insects, but they have also been known to take down larger prey, such as bats or mice. They've also been observed feasting on a carpet python, and a venomous red-bellied black snake.

They'll even eat other frogs. Basically, if it's small enough to go down the frog's gullet, and passes within chomping range, the frog is going to have a go. 

"It's relatively common (as far as frogs-eating-things go) to see Australian green tree frogs eating snakes," Rowley told ScienceAlert.

"They are 'garbage-guts'. Most frog species will actually eat anything that looks like it'll fit in their mouth that moves in front of them. It's instinct. They eat first (or try to) and think later. The frog likely just grabbed whatever bit of the snake it could, using its hands to try and shove it down."

For both reptiles and amphibians, it's a cutthroat world out there. As Stephen Sondheim wrote in his famous musical Sweeney Todd, "The history of the world, my sweet, is who gets eaten and who gets to eat."

If the frog hadn't eaten the snake, no doubt the snake would have eaten its share of frogs, as they form a crucial part of the diet of many snakes.

Snakes also munch on other reptiles, like this alligator lizard, who fought all the way down and apparently ended up escaping from its snake-belly doom. And a simple search for "python eats alligator" on YouTube yields up some interesting stuff, if you like watching animal violence.

If you know who took this photo, reach out to us on Twitter. We'd love to know more about it.

This story was updated on 19/10/17 with additional information from Jodi Rowley.