There are three artists named Heyoka:
1) Andrei Olenev a.k.a. Andreilien is a cosmic auditory scientist found in the Bay Area noosphere, who has been blowing minds with his sonic manipulations.
Muti Music first released Heyoka’s “Space Case EP” in 2008 and included him on their growing roster of talented artists. His albums 'Whomp Gland & Pineal Dub', 'Gate Code' and the all new 'Marklar' album in 2010 have shown that he is a producer consistently evolving his musical style while managing to maintain a signature sound that is distinctively 'Heyoka'.
His early influences in Downtempo, Dub and IDM combined with midtempo dancefloor genres have helped create a very unique sound that combines relentless basslines, hip hop rhythms, dub vibes, and musicality and melody, all within an atmosphere of heavy psychedelia and alien dimensions.
2) A French anarcho punk band formed in 1991. More information in French language here http://heyokapunk.free.fr
3) A progressive rock band from San Antonio's 70s underground scene. Most famous for their covers of Judas Priest's Victim of Changes and various Jethro Tull songs, they also produced many songs for various compilations and even recorded an entire full-length album only to have it never be released. Shroomangel records released a CD entitled Lost Tracks… Found which contains many of their most famous songs (aside from Disco Sucks) all on one CD and with each track remastered. There exists a few singles, a few compilation releases, and the full-length unreleased album along with various bootleg live material with varying quality.