For days and nights they battled the band that chewed their knees.
They killed to earn their living and to help out the conga ease.

The story:

I was humming the song in university and started singing the lines when someone behind me asked, "Why would they 'chew their knees?' Those aren't the right words to that song." I tried to argue it but I checked online later and was mortified to find out they're in fact the wrong lyrics!