This is a TARDIS-style police box keycap I made to fit Cherry-style keyboard switches. I was inspired by the glowing crystalline mini-TARDIS the Thirteenth Doctor has on her TARDIS console, though I based the design largely on the Eighth Doctor's version of the police box.
I wouldn't use this on a commonly-used key, it's made to stick out way above the rest of the keys, though normal keypresses do still work. Put the TARDIS on Scroll Lock or something equally-remote on a keyboard with LED lighting for a really neat effect. Put it on Escape for a thematically-appropriate function.
If you'd like this 3D model file to play with, I've also shared it freely here on Thingiverse
. If you'd like to buy a print, buying it right here on my Shapeways shop would be very cool of you.