Canooke - You could just print out a note at home that says, "(his name) steals food", and stick it to the fridge at eye level. He'll be embarrassed and it will likely deter him from doing it anymore because if he gets caught doing it after that note was on the fridge he'll look that much shittier.
If one must go down the revenge path, simple shit like this is the best option.
Fucking with their property involves a certain amount risk, especially if the office is equipped with security cameras. And since the thief has never been confronted for stealing, it doesn’t address the specific problem or send the intended message.
A note on the fridge, or applying something painful to the soda can creates a direct cause and effect, and let’s the culprit know exactly what’s going down. He also has zero recourse in such a scenario, as people are free to do whatever they want with their own consumables. He can’t go whining to management over the fact his mouth was scorched while trying to steal a soda, and the sodas owner can simply say, “yeah I like spicy shit,” even if he did.
Going around the office involving other people’s personal items, or fucking with his property, can absolutely get you fired. Rubbing a ghost paper all over the rim of a pop can will only get you laughs and the satisfaction of his pain.