Lord Death from Soul Eater
I like him the best, because there is a reason for his goofiness. He used to wear a much more serious and scary mask, because he is the grim reaper and everything was darker back in the past. He fought a war against the kishin and witches. Since he started a school to train young meisters for the future, he needed to change his image. He changed his mask, his voice, and how he acts. Thus, he became goofy and he is funny. Beware the reaper chops.
The most amusing part to me was when he was in a meeting with Medusa and yet he was joking around with Death Scythe and somehow talking about women’s underwear. Medusa was furious about these two goofs for this for completely legitimate reasons, but I still couldn’t help but laugh at that situation. I think I might be part pervert too….