Mannhai is a Finnish stoner rock / stoner metal band from Helsinki. The band was formed in the end of 1999 by bass player Olli-Pekka "Oppu" Laine and guitarist Ilkka "Ile" Laaksomaa. Soon they were accompanied by a young drummer Mikko "Junior" Pietinen and the following year by lead singer Jani "Joãnitor" Muurinen.
In 2004 singer Jani Muurinen left the band after three albums. In 2005 Mannhai got Pasi Koskinen persuated to replace Muurinen as a vocalist. Koskinen is best known for being the lead singer of Amorphis during the years 1996?2004.