It’s some kind of opuntia. You can see that the new pads growing look close to “plain ole” opuntia. Or you could if the plant wasn’t quite so deformed!
There are some variegated opuntias, perhaps that’s one of them.
It came in a small container. I just put in the mug until I found out what it was. Now that I know, I can throw it in, and watch it grow! Lol (Until it's eaten. )