Operation: Biowar, more generally known as Biowar, is a 19 level megawad created by Chris Harbin together with Paul Corfiatis and John Bishop. It was released in 1999, and features a combination of techbase and Hell levels but also some new themes including a snowy mountain. There are several new sound effects and textures but no changes in the regular Doom gameplay. The mod features music by well known composer Mark Klem.