You Fail To See
We're investigating back-stage at the town's theatre to find any clues of who might have poisoned the dead councillor, and how they might have done it. Investigating the dressing rooms of the various artists, perhaps sensing some evidence is close by, or that we are about to be ambushed by goblin ninjas, the DM asks us to make some Spot checks. He allows us to take out time, and asks 'What are your Spot check results if you take 20?', going around the table to get the results.
When it comes to Bert, he calmly says 'minus 20'.
'Minus 20?! What crazy arse negatives are you getting?'
'No, mine is 20.' Ah.