We had a co-worker we called the raccoon because of his scavenging habits. He was notorious for never chipping in for catered lunches (usually $5 for pizza and soda, or sandwiches, etc), but would somehow always show up to scavenge food right after lunch. The fact that he never paid was bad enough, but what really annoyed people was that he would take way more food than he could eat, and stash it in his desk until it went bad.
He also liked to swipe donuts when people brought them in. One day, he took four donuts out of the 24 available, and had them stacked on his desk. A co-worker walked by, saw the donuts, and grabbed one, saying "Oh, is that where all the donuts went? Thanks for saving me one!". What makes it worse is that he was diabetic, so what the hell was he thinking when he took four donuts?
He's since been fired (for good reason). We've had multiple layoffs over the past few years, and the in-house food is no longer a thing, which suits me just fine. Now, when people want to celebrate birthdays, etc, they go out to happy hours after work.