Please read the following paragraph in Morgan Freeman’s voice: And here we have the humble penguin, marching feet and all. Everything about the penguin is adapted for its semi-aquatic lifestyle, from its cheerful rotundity to its OH MY GOD WHAT IS UP WITH ITS MOUTH!?

For World Penguin Day, Nerdist would like to take a moment to remind you that for how adorable penguins are, their mouths are hellscapes. Open a penguin’s mouth, like the Enoshima Aquarium did in the video above, and you’ll find rows upon rows of backwards-facing spines.

The horrifying sight is a result of the penguin’s diet. Animals like you and me chew our food, usually dead food that won’t fight its way back up an esophagus. Penguins, on the other hand, eat their food — wet, wriggling fish — whole. To make the consumption of fish easier, especially underwater, penguins evolved spiked mouths and tongues to function like those tire spikes at a fancy parking lot — fish can proceed forwards (into the bird’s belly), but not backwards.

Other creatures have evolved a similar solution to eating slippery sea food. For whatever reason, I’m assuming most of us think that the interior of a turtle’s mouth is as docile as the animal. Not true for the leatherback sea turtle. Feasting almost exclusively on goopy jellyfish, the turtle’s mouth is as scary as a penguin’s. Actually worse.

A leatherback sea turtle esophagus is not the most inviting place.

Not only does a penguin’s mouth prevent backwards movement, its tongue is much like a sarlacc pit — ever undulating to facilitate movement from the front of the mouth to the back. Happy Penguin Day!

Have another animal mouth that surprisingly scary? Let us know in the comments below. Now look at this camel’s mouth.

Images: Enoshima Aquarium; gg; Karumbé