The taste of revenge
Food thieves are a known phenomenon around offices, and it doesn’t seem like they’re going anywhere. People have tried labeling their food with their names, but even that doesn’t seem to keep them away. This person kept bringing fresh doughnuts to the office, only to find that someone has eaten them without even asking. After the third time, he had found a way to keep people away from his doughnuts.
Mustard is good, doughnuts are good, so according to this logic, there’s no reason why doughnuts with mustard won’t be good, right? Well, we don’t want to find out. Doughnuts weren’t meant to be filled with mustard, and this seems like a classic office prank.