The man who calls himself Mr. Penguin (actually Monsieur Pingouin) hurt his hip in a car accident in 1968. After the injury, he walked with a strange waddle-like limp, and his colleagues started calling him Mr. Penguin (I’m assuming this was all in good fun).
From that point, he became obsessed with penguins. He learned everything he could learn about them, collected every piece of penguin-related memorabilia he could find, and eventually opened a museum in his home displaying 3,500 items. These days he often can be found walking around his Brussels neighborhood wearing a penguin costume. Eventually he hopes to be laid to rest in cold Antarctic waters in a coffin decorated with penguins.
I think this guy is great, and it speaks to the fun personality of Brussels. One of my favorite things about travel is getting a feel for each city's personality—every one is different—and I like Brussels’s personality. Mannekin-Pis, Mr. Penguin, Belgian waffles. If Brussels were a person, I’d want to hang out with him.
By the way, Mr. Penguin’s fame actually goes beyond Brussels. He has appeared on many TV shows over the years, and he was an honored guest at the Amsterdam premiere of Batman Returns back in 1992.