(I had this grand idea for a sci fi system where my players would be exploring a massive derelict vessel. It is only the second or third session when.)
Player 1. “So, can I use my repair skill to re-arm this defused landmine?”
(Me)DM. “You have knowledge of explosives so sure. Roll for it.”
Player 1. *rolls*
Player 1. *starts laughing uncontrollably, the rest of the party soon follows.*
(Me)DM. “That’s a nat 1 isn’t it. Oh god it is.”
I spent the next few minutes in shock as I figured out how I was going to have it play out.