Question: Who is the American bass guitarist known for his work in a virtual death metal band featured in "Metalocalypse"?

full_context: Document 1: Metalocalypse (season 3): The third season of the animated show "Metalocalypse" originally aired on Adult Swim from November 8, 2009 to October 24, 2010 with 10 episodes. The show follows virtual death metal band Dethklok. This season featured a 22-minute runtime (30 with commercials).
Document 2: The Dethalbum: The Dethalbum is the debut album by virtual band Dethklok, from American animated sitcom "Metalocalypse". It was released on September 25, 2007. The album features full length songs from the TV series, as well as previously unreleased tracks. Antonio Canobbio contributed the artwork for the record.
Document 3: Dethalbum III: Dethalbum III is the third full-length album by virtual death metal band Dethklok, from the Adult Swim animated series "Metalocalypse". The CD and deluxe CD/DVD were released on October 16, 2012. It contains music from the second, third and fourth seasons of the show. Like "The Dethalbum" and "Dethalbum II" before it, the music is performed by the show's creator Brendon Small and drummer Gene Hoglan. Additionally, the band's live bassist, Bryan Beller, performs on the album.
Document 4: Bryan Beller: Bryan Beller (born May 6, 1971) is an American bass guitarist known for his work with Joe Satriani, The Aristocrats, Dethklok, Mike Keneally, Steve Vai, James LaBrie of Dream Theater and Dweezil Zappa. He has been Joe Satriani's tour bassist for both the "Unstoppable Momentum" (2013–14) and "Shockwave" (2015–16) world tours in addition to featuring on the "Shockwave Supernova" record. Beller is also the bassist/manager of the rock/fusion super-trio The Aristocrats (with Guthrie Govan on guitar and Marco Minnemann on drums). The Aristocrats have released three studio albums, along with two live releases documenting the band’s world tours in support of their debut album "The Aristocrats" and sophomore album "Culture Clash". Their most recent studio album "Tres Caballeros" is the focus of their current world tour, which began in the summer of 2015 and will extend through to late 2016.
Document 5: Brendon Small's Galaktikon II: Become the Storm: Brendon Small's Galaktikon II: Become the Storm is the second solo album by Brendon Small, known for his work on the animated television shows "Metalocalypse" and "Home Movies", and as creator of virtual death metal band Dethklok. The album was released on August 25, 2017 through Megaforce Records. The album features Dethklok members Gene Hoglan and Bryan Beller, on drums and bass, respectively. Since Brendon Small no longer holds the rights to the Dethklok name, Gene Hoglan has suggested that this album would serve as a "new Dethklok album".
Document 6: The Aristocrats (band): The Aristocrats are a rock supergroup formed in 2011. The band consists of Guthrie Govan, Bryan Beller, and Marco Minnemann. The group name is inspired by the Aristocrats joke and consequently the song titles on their debut namesake album–a progressive rock compilation–are rife with salacious double-entendres.
Document 7: Dethklok: Dethklok is a virtual death metal band featured in the Adult Swim animated television series "Metalocalypse".
Document 8: Billy Sheehan: William "Billy" Sheehan (born March 19, 1953), is an American bassist known for his work with Talas, Steve Vai, David Lee Roth, Mr. Big, Niacin, and The Winery Dogs. Sheehan has won the "Best Rock Bass Player" readers' poll from "Guitar Player" magazine five times for his "lead bass" playing style. Sheehan's repertoire includes the use of chording, two-handed tapping, right-hand "three-finger picking" technique and controlled feedback.
Document 9: Brendon Small's Galaktikon: Brendon Small's Galaktikon is the solo album debut by Brendon Small, known for his work on the animated television shows "Metalocalypse" and "Home Movies", and as creator of virtual death metal band, Dethklok. The album features Dethklok members Gene Hoglan and Bryan Beller, on drums and bass, respectively. Small described the album as a "high-stakes, intergalactic, extreme rock album" and describes it as being similar to Dethklok but with more rock elements and melodic vocals. Like on previous Dethklok albums, Ulrich Wild produced the album and Antonio Canobbio designed the cover art. The album's release coincided with the premiere of the fourth season of "Metalocalypse". The album was also released on vinyl in late June 2012.
Document 10: Metalocalypse (season 1): The first season of the animated show "Metalocalypse" originally aired on Adult Swim from August 6, 2006 to December 17, 2006 with 20 episodes. The show follows virtual death metal band Dethklok. The majority of the music featured this season was released on the 2007 album, "The Dethalbum".
Document 11: Tony Markellis: Tony Markellis is a bassist and record producer from Helena, Montana, now residing in Saratoga Springs, New York. In his forty-five year career he has played blues, folk, jazz, rock and country music with musicians such as Trey Anastasio, Paul Butterfield, The Mamas & the Papas, Johnny Shines, David Bromberg, David Amram, Paul Siebel, Rosalie Sorrels, Eric Von Schmidt, Ellen McIlwaine, Mary McCaslin, Railbird and Jo Henley. Markellis was a founding member of the groundbreaking Vermont-based jazz fusion group Kilimanjaro, as well as the Unknown Blues Band featuring Big Joe Burrell. In the late 1990s, Markellis became the first member of the first solo band of Phish guitarist Trey Anastasio, forming the rhythm section with drummer Russ Lawton. Including his work with Anastasio, Markellis has appeared on over one hundred albums. In addition to tours with the Trey Anastasio Band, he is currently working with Kilimanjaro, acoustic blues power trios No Outlet and Street Corner Holler, The Burns Sisters Band, bluegrass fusion band Floodwood, acoustic Grateful Dead cover band Dead2Me, singer/songwriters Michael Jerling and Bob Warren, and occasionally with Americana band Jo Henley. On June 20, 2010 (Fathers Day), Tony was invited on stage at Saratoga Performing Arts Center (SPAC) to play bass with Phish on "Gotta Jibboo" (one of the songs he cowrote with Trey and Russ Lawton for the Trey Anastasio Band). Phish's bassist, Mike Gordon played the second guitar during the song.
Document 12: G3 (tour): G3 is a concert tour organized by guitarist Joe Satriani featuring him alongside two other guitarists. Since its inception in 1995, G3 has toured most years and has featured many guitarists, including Steve Vai (Satriani's former student), Eric Johnson, Kenny Wayne Shepherd, Yngwie Malmsteen, John Petrucci, Robert Fripp, Paul Gilbert, Steve Morse, Steve Lukather, Uli Jon Roth, Michael Schenker, Adrian Legg and many other special guests, including Tony MacAlpine, Johnny Hiland, Keith More, Chris Duarte, Andy Timmons, Neal Schon, Gary Hoey, Brian May, Billy Gibbons, Johnny A, George Lynch, Patrick Rondat, Guthrie Govan, Alejandro Silva, and Eric Sardinas.
Document 13: Backing musicians for Trey Anastasio: Since 1998, Trey Anastasio, best known from Phish, has toured and recorded with several backup musicians, including several side-projects organized and led by the guitarist and composer. While active, his bands did not have a name. Fans commonly referred to them as Trey Anastasio Band, or TAB for short or "The Two for Five band". This group should not be confused with the current Trey Anastasio Band, which was renamed in 2006 from its original name 70 Volt Parade.
Document 14: Metalocalypse (season 2): The second season of the animated show "Metalocalypse" originally aired on Adult Swim from September 23, 2007 to September 7, 2008 with 19 episodes. The show follows virtual death metal band Dethklok. The majority of the music featured this season was released on the 2009 album "Dethalbum II". The first episode of this season, "Dethecution" was released as part of the deluxe edition of "The Dethalbum". This season featured the new re-recorded version of the "Deththeme", released as a hidden track on "The Dethalbum".
Document 15: Brendon Small: Brendon Small (born February 15, 1975) is an American voice actor, stand-up comedian, producer, writer, animator and musician. He is best known as the co-creator of the animated series "Home Movies" (along with Loren Bouchard) and "Metalocalypse" (along with Tommy Blacha) and as the creator of the virtual death metal band Dethklok.
ground_truth: Bryan Beller