player rolls perception

DM: “you smell the distinct smell of gas building in the cave.”

Player: “I cast fireball.”

DM: “Alriiiiight… As the sparks ignite in your hand, the gas explodes, causing a cave in and burying the entire party under a mountain of rock. Congratulations, you are dead.”

Player: “Why didn’t you stop me?!”

DM: “You failed your wisdom check, dumbass.”

I hate it when the “and this is where we end the session for tonight” part happens 10 minutes in… once had a high level party teleport to the complete opposite side of the map 10 minutes after starting… That is when I learned what high level really meant.