What the hell is this? Well, it's "Babies With Teeth." From PetaPixel:
The project is the brainchild of Texas photographer Ashley Evans, and it all started while she was playing around in an app called YouApp.
“I had an app and wanted to see what my son looked like with teeth,” Evans tells PetaPixel. “It was hilarious so I did it to my daughter. I then posted in a Facebook group and it just blew up from there.”
Many of the images are accompanied by captions that adultize the babies, but I think they're just as funny without any description. See more at Babies With Teeth (Facebook).