It's a fantasy role-playing game.

DM: You are Grog Strongjaw, a goliath barbarian . You are the member of the famous group of adventurers. Previously, After slamming his feet into the sand and preparing himself for conflict, he beckons  you  towards him.  you faces off with Earthbreaker Groon.
DM: 21, that's right, yeah. So you manage to resist, the effect of the stunning strike. He's gonna go for the secondary attack.
Player: Okay.
DM: Which was seven plus 13, it's 20, so that still hits you.
Player: Yeah.
DM: You take 18, reduce that to nine.
Player: Oof .
DM: Make another constitution saving throw.
