This is a multi-function-device I unitentionally invented:
The double-sided-adhesive-tape dispenser capacitor (first pic)
It's a 900V / 15uF rated film cap that I use to test the output stability of that strange amplifier I'm building (second pic) for now. Otherwise, I use this capacitor to store a handy supply of that 3M VHB tape (it comes here in rolls of pizza size diameter)