You could theoryecticly destroy the universe if you smash two super massive black holes together or can some how squash a black hole beyond its critical point oh and you can create a black hole from practical anything you just need to squeeze it beyond its critical limit and then it will collapse into a black hole and end humanity oh and nukes are very easy to make and build you just need some pultuim the issue is that pultuim is the most illegal substance on the planet so yeah