Jason Jonathan Popson (born November 2, 1971[1]) is an American vocalist and rapper for metal band Mushroomhead taking the stage name J Mann.

Prior to his initial departure from the band he was identified by his face paint, which was based on the film Dead Presidents.

It has been hinted lyrically and in vague interviews that he was raised by a single parent—his mother—following the departure of his father from his life at a young age.

The concert acted as a benefit for his father's funeral, and featured Popson performing songs from many of his previous and current bands.

Popson is also in an extreme metal band with former Strapping Young Lad/Death drummer Gene Hoglan called Pitch Black Forecast, which also features Robert Reinard on guitar and Craig Martini recording studio bass.

A metal project by Popson, titled Scelestus (pronounced sha-less-tus), released an EP through Megaforce Records in May 2011.