Thanks to the magic of the Internet I now know;
Doc Bruce Banner
Belted by gamma rays
Turns into the Hulk
Ain't he unglamor-ays?
Wreckin the town with the power of a bull
Ain't no monster clown who is as lovable
As ever-lovin' Hulk!
People on Youtube complained it was a bad song but I think it has a charming, rough New Yawk wise-ass wit to it with the ain'ts and the goofy rhyme stretch - gamma rays and unglamor-ays
You have to admit there are few theme songs like it.