Mike Tyson, member of The Grateful Dead

Heard some music at work that reminded me of Mike Tyson's "Punch Out !!" , the montage were little Mac is training with his plus sized trainer ( Doc I think his name was) . It's a typical 80s beat.
Anywho, a song similar sounding came on at work today. It was the song " Touch Of Grey" by The Greatful Dead. It is, in all honesty, the only Dead song I've ever heard.
I'm saying though.. did The Greatful Dead secretly write the score for Mike Tyson's "Punch Out"?!??"
Was Tyson secretly in the band ?
And WHY did I always have trouble beating Great Tiger ?