Question: Pylon and Bullet for My Valentine, is what type of musical organization?

full_context: Document 1: Bullet for My Valentine: Bullet for My Valentine, often abbreviated as BFMV or B4MV, are a Welsh heavy metal band from Bridgend, formed in 1998. The band is composed of Matthew Tuck (lead vocals, rhythm guitar), Michael Paget (lead guitar, backing vocals), Michael Thomas (drums) and Jamie Mathias (bass guitar). Former members include Nick Crandle and Jason James; both were on bass. They were formed under the name Jeff Killed John and started their music career by covering songs by Metallica and Nirvana. Jeff Killed John recorded six songs which were not released; two of these tracks were reworked later in their career as Bullet for My Valentine. Financial difficulties dictated the name change, which was followed by a change in music direction. In 2002, the band secured a five-album deal with Sony BMG. The band has stated that their music is influenced by classic metal acts such as Metallica, Iron Maiden and Slayer. The band is part of the Cardiff music scene.
Document 2: Vietnam (band): Vietnam is a rock, post-punk and new wave band from Atlanta, Georgia on Scared Records. Vietnam first appeared at the dawn of a new decade—the 80's, and ushered in a fresh era of music to the Atlanta new wave scene. Embraced by the early 80's cavalcade of Athens bands such as R.E.M., Pylon, Method Actors, Love Tractor, etc., Vietnam wowed the patrons of the legendary 688 club, 40 Watt club, and the Agora Ballroom. Their first performance was opening for Public Image Ltd. in April 1980, and the next year they played the Noise Fest in New York, appearing on the ZG compilation release of the same name along with Sonic Youth, Glenn Branca, Y Pants and others. They released their first full-length album on Scared Records in 2004, "Past Away".
Document 3: Metallica discography: The following is the discography of Metallica, a Los Angeles-based metal band formed in 1981 by James Hetfield (lead vocals, rhythm guitar) and Lars Ulrich (drums). After several bassist and lead guitarist changes, the band settled on Cliff Burton and Kirk Hammett, respectively. Metallica started playing locally, releasing their first widely circulated demo, "No Life 'til Leather", in 1982. The demo caught the attention of Johny Zazula, who signed Metallica to Megaforce Records. The band released "Kill 'Em All" in 1983, and the following year they released "Ride the Lightning". After "Ride the Lightning" was released, Metallica left Megaforce and signed to Elektra Records. In March 1986, the band released its third studio album, "Master of Puppets", which was Metallica's first album to be certified gold by the Recording Industry Association of America (RIAA). While promoting the album, Burton was killed in a bus accident. Jason Newsted was hired as a replacement. The band's first release to feature the new member was "," and then followed by "...And Justice for All" in August 1988, which peaked at number six on the "Billboard" 200.
Document 4: List of Metallica concert tours: Metallica is an American heavy metal band, founded in 1981 by drummer Lars Ulrich and rhythm guitarist James Hetfield. Aside from Ulrich, the original lineup for some of the 1982 concerts included James Hetfield (rhythm guitar and lead vocals), Dave Mustaine (lead guitar and backing vocals) and Ron McGovney (bass guitar). Cliff Burton replaced McGovney in 1982 and played with the band until his death in 1986. After his death, bassists Jason Newsted (1986–2001), and Robert Trujillo (since 2003) were recruited in the band. While the lead guitarist role was taken by Kirk Hammett (since 1983) after Dave Mustaine got fired from the band.
Document 5: R.E.M.: R.E.M. was an American rock band that formed in Athens, Georgia, in 1980 by lead singer Michael Stipe, guitarist Peter Buck, bassist/backing vocalist Mike Mills, and drummer Bill Berry. One of the first alternative rock bands, R.E.M. was noted for Stipe's particular vocal quality and obscure lyrics, Buck's ringing, arpeggiated guitar style, and Mills' melodic basslines and backing vocals. R.E.M. released its first single—"Radio Free Europe"—in 1981 on the independent record label Hib-Tone. The single was followed by the "Chronic Town" EP in 1982, the band's first release on I.R.S. Records. In 1983, the group released its critically acclaimed debut album, "Murmur", and built its reputation over the next few years through subsequent releases, constant touring, and the support of college radio. Following years of underground success, R.E.M. achieved a mainstream hit in 1987 with the single "The One I Love". The group signed to Warner Bros. Records in 1988, and began to espouse political and environmental concerns while playing large arenas worldwide.
Document 6: Jeff Killed John (EP): Jeff Killed John is the last EP by Welsh nu metal band Jeff Killed John, before changing their name to Bullet for My Valentine. This EP also marks the last recorded material with bassist Nick Crandle, before Jason James replaced him. Many song elements from this EP would be reworked into later tracks for Bullet for My Valentine music: "Routine Unhappiness" contains riff elements that would later become "Tears Don't Fall," with lyrical content that would appear on "10 Years Today;" "Nation2Nation" would eventually become the bonus track "Turn to Despair" on the Japanese edition of "Hand of Blood;" and "All These Things I Hate (Revolve Around Me)" is an early demo of the song of the same name that would eventually appear on Bullet for My Valentine's debut album "The Poison."
Document 7: Randall Bewley: Randall Eugene "Randy" Bewley (July 25, 1955 – February 25, 2009) was the guitarist for the Athens, Georgia band Pylon. Born in Bradenton, Florida, United States. He lived in Sarasota, Florida, Washington, DC and near Atlanta, Georgia while growing up. Bewley attended the University of Georgia art school where he met Michael Lachowski, a fellow art student. They became roommates and decided to form a band. He and Lachowski, along with fellow art students Vanessa Briscoe Hay and Curtis Crowe, formed the band, Pylon, having their first performance in 1979. On their first trip to New York City, they were written up in "Interview Magazine".
Document 8: Metallica: Metallica is an American heavy metal band based in San Rafael, California. The band was formed in 1981 in Los Angeles when vocalist/guitarist James Hetfield responded to an advertisement posted by drummer Lars Ulrich in a local newspaper. Metallica's current lineup comprises founding members Hetfield and Ulrich, longtime lead guitarist Kirk Hammett, and bassist Robert Trujillo. Guitarist Dave Mustaine (who went on to form Megadeth) and bassists Ron McGovney, Cliff Burton, and Jason Newsted are also former members of the band.
Document 9: The Primates: The Primates were one of the original post-punk / rock bands to come out of Athens, Georgia in the mid 1980s. Their loud, fast in-your-face hedonistic style is reminiscent of West Coast bands X and The Minutemen, but peppered with a definite influence of traditional country music. The Primates consisted of Eric Sales - bass and vocals, Greg Reece - guitar and vocals, and LH Sales, Jr. - drums and vocals. Before going three-piece, early in the first years The Primates had a second rockabilly style guitarist - Mike Whigham. They at one point served as GG Allin's backing band.
Document 10: Pylon (band): Pylon were an American rock band from Athens, Georgia. The band's danceable sound, a blend of new wave, post-punk, jangle pop, alternative rock and funk rock, influenced the Athens music scene and the 1980s American pop underground. AllMusic wrote that Pylon's "role as elder statesmen of the alternative rock explosion is unassailable".
Document 11: List of rock genres: This is a list of rock music genres consisting of subgenres of popular music that have roots in 1940s' and 1950s' rock and roll, and which developed into a distinct identity as rock music in the 1960s, particularly in the United Kingdom and the United States. By the late 1960s, a number of identifiable rock music subgenres had emerged, including hybrids like blues rock, folk rock, country rock, and jazz-rock fusion, many of which contributed to the development of psychedelic rock influenced by the counter-cultural psychedelic scene. New genres that emerged from this scene included progressive rock, which extended the artistic elements; glam rock, which highlighted showmanship and visual style; and the diverse and enduring major subgenre of heavy metal, which emphasized volume, power, and speed. In the second half of the 1970s, punk rock both intensified and reacted against some of these trends to produce a raw, energetic form of music characterized by overt political and social critiques. Punk was an influence into the 1980s on the subsequent development of other subgenres, including new wave, post-punk and eventually the alternative rock movement. From the 1990s alternative rock began to dominate rock music and break through into the mainstream in the form of grunge, Britpop, and indie rock. Further fusion subgenres have since emerged as well as conscious attempts to revisit rock's history.
Document 12: Of Montreal: of Montreal is an American experimental pop band from Athens, Georgia. It was founded by frontman Kevin Barnes in 1996, named after a failed romance between Barnes and a woman "of Montreal." The band is identified as part of the Elephant 6 collective. Throughout its existence, of Montreal's musical style has evolved considerably and drawn inspiration from numerous 1960s psychedelic pop acts.
Document 13: Matthew Tuck: Matthew "Matt" Tuck (born 20 January 1980) is a Welsh musician. He is the lead vocalist and rhythm guitarist in the Welsh heavy metal band Bullet for My Valentine. He and the other 3 members of his old band founded "Jeff Killed John" in 1998, but after bassist Nick Crandle left in 2003, the band was renamed to Bullet for My Valentine. He is also a singer and guitarist in the supergroup AxeWound, which was formed in 2012. He also plays piano, drums, keyboard, and harmonica. He did a collaboration with Max Cavalera (Soulfly, Cavalera Conspiracy, ex-Sepultura) and with Apocalyptica in the song "Repressed".
Document 14: Michael Lachowski: Michael Scott Lachowski is the bass guitar player for Pylon, a band from Athens, Georgia. He was born in Norfolk, Virginia and attended the University of Georgia art school. He and his roommate Randy Bewley formed Pylon, recruiting Curtis Crowe as a drummer, and Vanessa Briscoe Hay, a fellow student at the University of Georgia. They recorded the single "Cool/Dub", an album "Gyrate", an EP, another album "Chomp", and two singles. Pylon toured the United States, Canada and the United Kingdom before breaking up in 1983. They returned to tour again in 1988, and recorded another album, "Chain", in 1990, before breaking up again in 1991. Pylon reformed in 2005 and occasionally performed until 2009, when Bewley died.
Document 15: List of songs recorded by Metallica: Metallica is an American heavy metal band formed in Los Angeles, California in 1981. The band released its debut album "Kill 'Em All" in 1983, which credited songwriting between frontman James Hetfield, drummer Lars Ulrich and guitarist Dave Mustaine, who had left before the album was recorded (bassist Cliff Burton was credited for the bass solo "(Anesthesia) – Pulling Teeth"). On the 1984 follow-up "Ride the Lightning", Burton received more songwriting credits and Mustaine's replacement Kirk Hammett was also co-credited on four songs. "Master of Puppets", released in 1986, was the last album to feature Burton, who died in a bus accident later that year.
ground_truth: band