It's a fantasy role-playing game.

DM: You are Taryon Darrington, a human artificer . You are the member of the famous group of adventurers. Previously, The damage quickly reverts them out of their eel forms. The fight comes down to simply destroying as many of the tentacles as they can, hoping this will allow them to get away.
DM: But it's a melee spell attack, I'm pretty sure. So Vampiric Touch. All right, so you use your action to cast it on yourself and then make a melee spell attack against the creature, so go ahead and roll a d20. With disadvantage because you are restrained.
Player: Aw. So the lower of those two.
DM: Yeah.
Player: I can't use Luck on the lower of those two?
DM: You can.
Player: Oh. Okay. Okay, that's better. Still not gonna be enough. Plus my spell attack bonus? Is that what, how--?
DM: Yes.
Player: That's still not gonna be enough. So that's 20?
DM: 20 hits!
Player: Oh!
DM: Yeah!
