Help with level 6 - battling the "big Boss"

I'm at the end of level 6 - battling the "Big Boss" - what in the world do I do to defeat this thing?? I've been "Killed" several times before I even know what's happened!! Are there any suggestions for how to defeat the Big Boss before he gets me again?? I'm getting sick of repeating this level again and again. I've done extremely well up to this point. But, He's huge so jumping on his head isn't much help, especially with him throwing large "rocks" at Super Cow. Any hints before I die yet again??? Thanks!!