When Kirby was introduced in 1992 in Kirby’s Dream Land, he was just a pink spherical thing with starry-eyes, a mouth, two flaps for arms, and two round potato-y feet.

Back in March, illustrator Marie Blue posted a drawing of Kirby sans shoes, revealing two pink, sort-of-human feet.

On Monday, a gamer’s development of a mod for Kirby in Super Smash Brothers for Wii U took this one step further, with a Kirby that’s most definitely got human feet.

Kirby super smash bros fighting video games mario wii u nitendo
Kirby and Mario duke it out in the Wii U version of Super Smash Bros.

It’s gotten a few downloads and more than a few comments from people not into Kirby’s humanoid feet — whether they’re disgusted by human feet, people touching feet, or just plain ol’ feet in general.

And that’s not exactly that surprising on its own: Feet are sweaty and smelly, and they come in contact with the ground. This makes them seem dirty and germ-infested. Over time, humans have evolved to be disgusted by things that could potentially make them sick and die.

This reaction to feet is linked to a primitive part of the brain known as the insular cortex, the part of the brain that processes basic emotions like happiness, sadness, anger, fear, and disgust. The insular cortex is also where the brain processes sexual arousal. Researchers have seen an interaction between sex and disgust which may explain why some people might actually get turned on by feet while others get turned off.

Masashiro Mori Explains the Uncanny Valley Effect in Human-like Renderings

Kirby’s creepy foot might also be emblematic of the discomfort of seeing something not quite human, or the uncanny valley effect. The idea of uncanny valley effect was developed in the 1970s by Masahiro Mori. The Japanese roboticist noticed that people became uncomfortable when they saw robots that were close to but not completely human. As a robot becomes more human-like, there comes a point before, but then quickly drops, but then hikes back up as the robot moves towards 100 percent human-likeness.

According to researchers anything with a highly human-like appearance — robot, computer game characters, even sex dolls — can present the uncanny valley effect. Some researchers believe people feel the effects of the uncanny valley because they see the humanoid as having a mind of its own. Studies have shown that robots are less scary when people saw them as not possessing a mind. People are also subjected to the uncanny valley when they see conflicting representations like a human-like figure having robotic movements.

And those human feet in pudgy, otherwise adorable Kirby? It freaks people out because their brains can’t figure out if it’s human or not. A moment to paws, perhaps?

Photos via Ali Naqi / WCCFTech, Masahiro Mori / Dartmouth College, LuckyJero / GameBanana