OK, you're probably confused as to what M.F.K.R. is, but you probably already know it's something to do with Slipknot. Basically, it was Slipknot's very first recorded content, a demo. It stands for "Mate. Feed. Kill. Repeat." It was released in 1996 and there were only 1,000 copies made. The band members at the time were different to the members now (2009). Slipknot considers M.F.K.R as a demo, and that the band has evolved greatly since they recorded it.
Maggot 1: "I'm listening to M.F.K.R."
Maggot 2: "Sounds familiar, what is it?"
Maggot 1: "Slipknot's first music recording."
Maggot 2: "I thought their first album was self-titled?"
Maggot 1: "This was before that!"
Maggot 2: "I still don't get it, let me check Urban Dictionary"