Okay, so I started to talk about this as a comment on one of Tyler's posts, but I wanted to expand on it here. As I was reading the book, Oskar reminded me a lot of Alex from the movie (and novel, but I've never read that...) A Clockwork Orange. I don't know if anyone has seen it, but it's about this teenage guy who leads a small gang that enjoys "ultra-violence." Alex and his followers prey on the weak and unsuspecting by beating up random people on the street, breaking into houses and violently gang raping women, and any other sort of violent and/or sexual shenanigans that they find amusing. It's weird and creepy and wonderful, you should all watch it.
Anyway, Oskar and Alex are both extremely self-centered and have tendencies to turn violent attacks into lighthearted occasions. Like Oskar, Alex is presented as an extremely unreliable narrator. He focuses only on his own sick interests and views brutal and horrible events as entertaining and exhilarating. At one point, he beats up and cripples a man while happily singing "Singing In The Rain," then rapes his wife in front of him. Alex also knew how to use his charm to play the system to his advantage, much like Oskar's reliance on the "helpless three-year-old" act to get him out of trouble. Additionally, Alex loves the music of Beethoven and, while undergoing psychological treatment, is "brainwashed" into associating Beethoven's music with pain and violence, physically torturing him whenever he hears it. Although he loves violence and destruction, he loves art and Beethoven just as much. This reliance on art in the midst of violence reminded me of Oskar's reliance on drumming and the damage he does with it, constantly combining art and destruction.