A demon core was part of early nuclear bomb research. The type of reaction they were studying would emit blue light and a ton of radiation.
https://en.wikipedia.org/wiki/Demon_core
It’s been a meme to imagine the demon core as an available weapon in medieval fantasy, since it looks somewhat like a mace.
Pascal was a famous thinker of their time, particularly in mathematics.
Two of the ideas they’re remembered for are Pascals Triangle and Pascals Wager.
Their triangle is a helpful tool for combinations of things. Their wager is a (kinda bad in my opinion) argument for why you should believe in the Christian God.
The xkcd comic is a combination of both ideas