Question: Who was the Vocalist for the Album Turn to Stone by Pentagram?

Context paragraphs:
Pentagram (band): Pentagram is an American heavy metal band from Alexandria, Virginia, most famous as one of the pioneers of heavy metal, and the subgenre of doom metal in particular.  The band was prolific in the underground scene of the 1970s, producing many demos and rehearsal tapes, but did not release a full-length album until reforming in the early 1980s with an almost completely new lineup.  Throughout the band's history the only constant member has been vocalist Bobby Liebling.  The revolving lineup of Pentagram has featured many well respected musicians in the local doom metal scene, with members spending time in other acts such as Raven, the Obsessed, Place of Skulls, Internal Void, Spirit Caravan, among many others.

List of songs recorded by Stone Sour: Stone Sour is an American alternative metal band from Des Moines, Iowa.  Originally formed in 1992 by vocalist Corey Taylor, guitarist Josh Rand, bassist Shawn Economaki and drummer Joel Ekman, the band was active until 1997, when Taylor left to join Slipknot.  Guitarist Jim Root, who had joined the band later, also joined Slipknot in 1999.  Stone Sour reunited several years later, releasing its full-length debut album "Stone Sour" in 2002 which featured songs from early demos. Ekman was replaced by Roy Mayorga in 2006, who performed on the band's second album "Come What(ever) May".  The songs on the album were written by Taylor, Root, Rand and Economaki.

Turn to Stone (album): Turn to Stone is a compilation album by Virginia doom metal band Pentagram, comprising songs from their first three albums: "Relentless", "Day of Reckoning" and "Be Forewarned".  It was released by Peaceville Records in 2002.

Teenage Time Killers: Teenage Time Killers is a rock supergroup formed in February 2014 by My Ruin guitarist Mick Murphy and Corrosion of Conformity drummer Reed Mullin.  Guests include Dave Grohl (former drummer of Nirvana and current lead singer of the Foo Fighters), Stephen O'Malley (of Sunn O))) and Burning Witch), Corey Taylor (lead vocalist of Slipknot and founder of Stone Sour), Nick Oliveri (former bassist for Queens of the Stone Age, currently with The Dwarves), Jello Biafra (former front man of Dead Kennedys, currently with The Guantanamo School Of Medicine), Matt Skiba (vocalist and guitarist of Alkaline Trio and current guitarist and vocalist for Blink-182) and Randy Blythe (lead vocalist of Lamb of God).  The band's name refers to the Rudimentary Peni song of the same name.  Their debut album, titled "Teenage Time Killers: Greatest Hits Vol.  1", was recorded at Grohl's Studio 606, and was released July 28, 2015.  through Rise Records, with whom the group signed in December 2014.  The album contains a version of John Cleese's poem "Ode to Hannity," sung by Biafra.  Mullin has stated that he isn't sure whether the group will tour, but that they are considering a live appearance on a show such as "Jimmy Kimmel Live! ", possibly with "three or four singers [coming] out at a time".

Turn the Tide (album): Turn the Tide is the second album from country music group Baillie & the Boys.  It was a number 30 Country Album on Billboard charts.  Its Hot Country Singles hits were, chronologically, "Long Shot" at number 5, "She Deserves You" at number 8, "(I Wish I Had a) Heart of Stone" (their highest-charting single) at number 4, and "I Can't Turn the Tide" at number 9. " Safe in the Arms of Love" was later recorded by Michelle Wright in 1994 and Martina McBride in 1995, both of whom released it as a single.

Stone Temple Pilots (album): Stone Temple Pilots is the sixth studio album by American rock band Stone Temple Pilots.  The album was released worldwide from May 21 through May 27, 2010, and is the band's first album since 2001's "Shangri-La Dee Da".  The album is the result of the band's reunion, which occurred in April 2008 with their North American tour.  After Stone Temple Pilots had begun playing together, the band decided to record again, but a lawsuit filed by Atlantic Records on June 12, 2008, made the sixth album an uncertainty.  Atlantic eventually withdrew the lawsuit, and the band's attorney called the legal situation a "misunderstanding".  This is the last album to feature vocalist Scott Weiland before he was fired from the band in 2013 and died in 2015.

Witchcraft (Witchcraft album): Witchcraft is the debut album from the Swedish doom metal band Witchcraft.  The album was released in 2004 by Rise Above Records.  "Please Don't Forget Me" and "Yes I Do" are both covers of 70s-era Pentagram.  "Yes I Do" appears on the original LP version and the Japanese press; it does not appear on the picture disc.  "Please Don't Forget Me" is credited to Bobbly Liebling on the sleeve and is often mis-accredited to Liebling's pre-Pentagram outfit, Stone Bunny.  The cover image is a slightly altered version of a print called "Merlin", a pen-and-ink drawing by Aubrey Beardsley for an 1893-94 edition of Sir Thomas Malory's "Le Morte d'Arthur".  Additionally, the band formed to be a one-off tribute band to both Bobby Liebling and Roky Erickson, and only intended to make one song (No Angel or Demon) however, they continued and are now an original band.

MMXII (Mezarkabul album): MMXII is the sixth studio album of Turkish heavy metal band Mezarkabul (also known as Pentagram).  "Wasteland", the first single from the album, was released before the album as a free digital content on band's official website.  MMXII is the first album of Mezarkabul with their new vocalist, Gökalp Ergen.

Vishal Dadlani: Vishal Dadlani (born 28 June 1973) is an Indian singer, music record producer, composer, lyricist and performer.  He is the vocalist/songwriter of the indie rock/electronica band, Pentagram, founded in 1994, regarded as one of the pioneers of original Indian independent music, having received recognition locally as well as globally.  He is also one half of the Bollywood composing/producing and performing music duo Vishal-Shekhar, since 1999.  They are credited with being amongst the architects of the modern Bollywood sound, having composed for 60 films and released over 300 songs, and performed over 1,000 shows worldwide.  Vishal has always supported Indian independent music, and helped many artists and bands find their feet.  Raghu Dixit, now a hugely successful artist in his own right, is one of Vishal's earliest proteges.  Vishal and Shekhar released Raghu's first album to great success, in 2008.  Vishal's involvement as a jury member in many of India's biggest music talent hunts including, "Sa Re Ga Ma Pa" 2007 and 2010, "Indian Idol Junior" 2013 and 2015, "The Stage" 2015, have been prominent in highlighting his constant search for, and encouragement of, fresh talent in both, the mainstream and the Indian independent music scene.  Vishal also co-founded indie-giant Only Much Louder with Vijay Nair in 2002 and exited a couple of years ago.  Vishal is equally at home with indie music, rock, electronica, hip-hop and Bollywood sounds, has now launched his own label in 2015 called VLT (Vishal Likes This) to create a wider platform for indie artists in India.

A Keg Full of Dynamite: A Keg Full of Dynamite is a live album by Virginia doom metal band Pentagram, released by Black Widow Records in 2003.  It was recorded at The Keg in 1978.  Vocalist Bobby Liebling stated that this was the "first authorized representation of Pentagram during what has come to be known as the High Voltage Era".  The final two tracks, "When the Screams Come" and "Livin' in a Ram's Head," were taken from the original test pressing 7" issued on High Voltage Records in 1979.

Supporting paragraphs: Turn to Stone (album) Pentagram (band)
Answer: Bobby Liebling