Wikipedia
Hellbassbeaters is the debut album by Helloween bass player Markus Grosskopf's bass guitar based heavy metal side project Bassinvaders. The album was released on 25 January 2008 in Germany.
The album is a distinctive piece of experimental music which features no guitars at all. Instead, it features lead solo bass guitars, rhythm bass guitars and actual bass guitars who play the bass parts, along with accompanying vocals and drums. Most notably, the album features the Bassinvaders' rendition of Helloween's popular song "Eagle Fly Free".
Also, the album features a wide range of guest bassists who play the bass solos and add to the variety of the album. Those include Billy Sheehan ( Mr. Big, Steve Vai), Rudy Sarzo ( Dio, Quiet Riot), Jan S. Eckert ( Masterplan), Tobias Exxel ( Edguy), Marco Mendoza ( Blue Murder, Whitesnake), Nibbs Carter ( Saxon) and more.