It's a fantasy role-playing game.

DM: You are Scanlan Shorthalt, a gnome bard . You are the member of the famous group of adventurers. Previously, you then asks the final question, from one father to another. The questions having been asked and the magic fading, the body reverts to its lifeless state.
DM: It's just 11. All right, and one of them takes five points of damage and (impact sound) looks down at this little gnome that's there.
Player: No, no, I'm still invisible. It's not a concentration spell.
DM: Invisibility, I'm pretty sure that as soon as you do--
Player: Oh, fuck.
DM: The spell ends for a target that attacks or casts a spell.
Player: Casts a spell?
DM: Yeah.
Player: Even though it's a concentration spell?
DM: Yeah, you can cast other instantaneous spells, but as soon as you cast a spell you become visible.
Player: What?
DM: High-level invisibility, improved invisibility is the one that remains.
