Never, that's when.
There are many pictures of him pawing at the cup so maybe he's an auction house employee?? If so, maybe next time they have a major painting like the Cezanne that sold for ~260 mil, he could suddenly come running out with a bucket and announce that it's full of acid. Everyone gasps and recoils in horror.
Let the gravity of the situation sink in for a moment then just as suddenly he could turn and dump it at the painting but ----> confetti.
The Harlem Globetrotters gambit.
The guy has material available to him.