When you want to make a fall on the grenade but the grenade turns out to be bigger than you expected!
Derived from the tsar bomba which was the most powerful nuclear bomb ever detonated.
Dude1: Dude! Last night I had to take one for the team and sacrifice myself by fucking the fat chick. But she was such a fatty that I thought I am not gonna survive this night!
Dude2: It's ok buddy. Somebody had to fall on the grenade.
Dude1: It was not just a grenade! It was a nuclear bomb!
Dude2: So it was a fall on the tsar i guess.