"M is for Mooley" is a parody of Sesame Street's "C is for Cookie". This was not a full parody but rather a clip Keyz sang in response to being in last place in the 2006 NFL Picks competition due to 'poor officiating'. Had he lost, Keyz would have had to get a Brazilian waxing.
M is for mooley, the cheating referee.
I'd like to take and hang him from a fucking tree. That
sack was not roughing the passer anyone could see, but
now 'cause of him,
soon, my balls will