All the Sucker Branches

In the season 5 episode Weight Loss, Michael and Holly randomly break out into a rap song in the warehouse nicknamed "All the Sucker Branches", further expanding their friendship. It is in the style of 1990s hip-hop, with references to DJ Jazzy Jeff and MC Hammer, both rappers in the 1990s. The lyrics to this song can be found below.

Lyrics
Michael: I'm MC Mike Scott and I am hot!

Michael: She's DJ Jazzy Flax and she is the best!

Michael: All the sucker branches can suck our fat!

Holly: Wikka Wikka Wikka Whaaat?!

References to Hip-Hop
The song is in the style of 1990s hip-hop, with references to DJ Jazzy Jeff and MC Hammer, both rappers in the 1990s. "Wikka wikka wikka what" is supposed to simulate the sound of scratching records, a common theme in 1990s hip-hop.

References to Episode
In the episode Weight Loss, the entire Dunder Mifflin company is taking part in a contest to see which branch will lose the most weight. That is what "All the sucker branches can suck our fat" means.