By the way, if you sue somebody because you ran into their parked car with your bike, you're broadcasting to the world that you are literally dumb enough to get hit by a parked car.
They're parodies in style, rather than specific songs. For example, Trigger Happy's supposed to sound like The Beach Boys, I'll Sue Ya's supposed to sound like Rage Against The Machine, and Bob's supposed to sound like Bob Dylan. One of my favorite bands of all time, Ween, is also known for doing that kind of thing.