Allen attended the University of Oklahoma starting in 1993, and was a true freshman for the Sooners, such as rushing for 102 yards against the Texas Longhorns in a 38–17 victory.
[2] The following year, Allen was stopped at the goal line in a loss to the Longhorns, and was later replaced by De'mond Parker in 1996, though Allen would score the game-winning touchdown that season against the Longhorns, giving the 3–8 Sooners the 30–27 win.
[7] Allen was the Bears starting halfback,[8] and in 2000, he led the team with 1,120 rushing yards and two touchdowns.
[14] However, in 2003, Allen retired from the NFL to become a rapper under the stage name Mersilis,[15] saying that he "lost a little bit of that fire".
[16] Allen had skipped the Texans preseason game against the Denver Broncos due to "personal issues".