It's actually called "Le Nux" but it had to be changed so it wasn't too controversial for the rest of the world

Have you never heard of black pudding or bludwurst?

Middle bottom is the demon core, an extremely radioactive orb:

https://en.wikipedia.org/wiki/Demon_core

And anyway, there's a new physics demon now:

https://www.newscientist.com/article/2386751-demon-particle-found-in-superconductor-could-explain-how-they-work/