P.O.S (born Stefon Alexander), is a rapper signed to Rhymesayers Entertainment and a founding member of Doomtree. In 2001 P.O.S, along side rapper Syst (short for system) and DJ Anamoly (Jason Heinrichs) existed as a short-lived hip-hop group called Cenospecies. They stayed together long enough to put out an album titled Indefinition (2002). The group won the award for Best Band to Break Up in the Past 12 Months in the year-end issue of The City Pages.