"Wait until you realize that there is no door", says the oracle.
DM: You come to a doorway but there is no actual door. The passage continues 30ft ahead.
Brother Candle: "Let us give thanks to the keeper of doors and pray for its speedy return."
Paranoid Albert: "But
why is there no door here? It could be a trick! Perhaps it's an invisible door?"
Fingers McThumb: "I steal the ... um ... I examine the ... um ...
doorway. Yes, that's it, I examine the doorway."
DM: The doorway is worked stone, quite old, and built into the wall. There is a faded inscription carved above it, which reads, in common,
THIS IS NOT A DOOR.
Paranoid Albert: "I told you it was a trick! No-one would write that if it wasn't a trick! I push Fingers through the doorway in front of me."
Fingers McThumb: "Hey, no pushing! I'm wearing my
Dwarven Boots of the Firm-Footed. I resist the push."
DM: Albert, I'll treat that as a Shove attack with disadvantage because of the Boots.
Brother Candle: "Gentlemen, gentlemen, let us not fall to petty squabbling. I will cast
Detect Missing Doors.
DM: You do not detect a missing door.
Paranoid Albert: "Oh no! It's an invisible door that resists detection! I put down my torch, close my visor and grip my halberd firmly in both hands. I have the Alert feat and cannot be surprised."
Fingers McThumb: "I
Hide in Albert's shadow."
DM: Albert, as you douse your torch and your eyes become accustomed to the gloom, you see that the corridor is dimly-lit by phosphorescent moss. Fingers, make a
Stealth roll, please, but with Disadvantage because there are no actual shadows.
Brother Candle: "The gods have warned me not to touch the moss. It is living moss formed from the bones of the long-dead door by evil necromacy. Ahead lies the lair of a half-elf necromancer."
DM: How did you know that? Have you been reading the module? Bah! Now I'll have to change it. Okay. 30ft ahead there is a door ...
"I told you it was a trick."