Sento Oumi, the protagonist of Fight Ippatsu! Jūden-chan!!, has a terrible temper and tends to hit "magical" girls who annoy him with a baseball bat. Now, this could be seen as rather disturbing, but I figure we've seen enough angry anime girls beat up the guy for comedic affect. It's still cartoon violence. Feel terrible for the cute girls though, aww.
Not a onyesha for younger viewers though, since some of the female characters discover their own masochistic tendencies after getting hit with the bat.