In the year 2OXOXOXO, Dr. Lighly bought the DIY construction kit for a unique and questionably-powerful robot maverick masterbottroncon. After being reprogrammed by the wily Dr. Wight, this megamiraskulgreybotmonchu has taken control of a green, pleasant land filled with giant cats, Christmas lights, flowing streams of Larry Cola, and a sweaty, suffering mid-level boss in a green shirt straining for relief. What sort of opponent awaits us at the end of this pleasant, charming stage? Should one even bother to reach him if it will mean the end of this beautiful music? Why can't I shoot up?

tl;dr version - I'm pretty sure this is Bertn Man's stage music.