Just noticed it seemed so familiar when I heard Stewies rival kid voiced by Doug Benson was dancing to it

Here's a thought experiment/test:

If you know the Gruntildas Lair theme tune, try reading these lyrics to the tune in your mind (if you havent heard it or cant remember, have a listen on Youtube first):

If you go down to the woods today\

You're sure of a big surprise.\

If you go down to the woods today\

You'd better go in disguise!
\

For every bear that ever there was\

Will gather there for certain,
Because

Would be hella coincidence otherwise