Pain is a hand-sculpted artisan keycap made for mechanical keyboards which can be used as a replacement for any key. It is designed to fit comfortably in the escape row on cherry keysets and should work with any MX style switch.
Unlike most keycaps, Pain features an opening in the back left allowing you to string it from a keychain, a necklace, a bracelet, or anything else you like.
If you're curious about the sculpting process and seeing how it's evolved over time you can view progress shots here.
This Listing is for the colorway "Sea of Rust" which features a ~30% copper outer layer and a glow in the dark blue inner layer, which can make for some fun back lighting. As this colorway is made with real metal it can be polished with steel wool, although the top right corner in the back and the teeth on the front are especially fragile and must be done carefully.