These are Cuddle Clones Plush Slippers, custom house slippers designed to look just like your pet. You just send a photo of your cat or dog along with a digital payment of $199, and eight weeks later you're wearing your pet on your feet -- simple as that. Also creepy as that. Still, it looks like they do a pretty great job of capturing the likeness of a pet. The custom stuffed animal I paid someone on Etsy $120 to look just like my pet? Not so much. "Cute bulldog." Thanks, it's supposed to be a turtle.
Keep going for a bunch more examples. Also, that cat with the crazy white mustache definitely could have used some more whiskers.
Thanks to Closet Nerd, who agrees there's nothing wrong with wearing slippers to work on Casual Fridays provided it isn't raining.