First, I thought it was:
I'll keep you by my side with my superhuman -- I ate the crypt tonight.

I realized that was wrong, but then I thought the correct lyrics were:
I'll keep you by my side with my superhuman -- I hate the Kryptonite

The story:

I was singing the first version, and my brother looks at me and goes, "What did you just sing??" I repeated it, and he almost fell off his chair laughing. He told me the lyrics were the second version, and I was like, "Oh. I'm going to stop singing along with the radio now..."