Question: Which of the two people who wrote the screenplay for "Dead & Buried" a 1981 science fiction horror film, also worked as a director, visual effects supervisor, and occasional actor?

Context articles: Christopher Townsend
Dan O'Bannon
Visual effects supervisor
Paul Franklin (visual effects supervisor)
Dead &amp; Buried
Greg Butler (visual effects supervisor)
John Knoll
Nick Allder
Richard Bluff
Kaj Steveman

Christopher Townsend is a visual effects supervisor.
 He has worked in the visual effects industry for over 20 years.
 For over a decade, he was an artist and supervisor at Industrial Light and Magic, and in 2007 became a freelance visual effects supervisor.
 He worked on "Journey to the Center of the Earth", the first ever stereoscopic motion picture shot and released digitally, "Wolverine", "Ninja Assassin", "" and "".
 He was nominated for a BAFTA and an Academy Award for Best Visual Effects for his work on "Iron Man 3", oversaw nearly 3000 shots on "" and was the overall supervisor for "Guardians of the Galaxy Vol.
 2".
 In 2015 he was given an Honorary Doctor of Arts degree by his alma mater, Coventry University.
Daniel Thomas "Dan" O'Bannon (September 30, 1946 – December 17, 2009) was an American film screenwriter, director, visual effects supervisor, and occasional actor, usually in the science fiction and horror genres.
In the context of film and television production, a visual effects supervisor is responsible for achieving the creative aims of the director and/or producers through the use of visual effects.
 While it is a creative role, most supervisors possess a strong technical background and are capable of making informed decisions about the most efficient and effective technique to employ to solve the problem at hand.
 Often a supervisor will work in tandem with a visual effects producer and computer graphics supervisor.
Paul J. Franklin is an English visual effects supervisor who has worked with visual effects since the 1990s.
 He is known for his long-running working relationship with director Christopher Nolan which dates back to "Batman Begins" (2005).
 Franklin won the Academy Award for Best Visual Effects and the BAFTA Award for Best Special Visual Effects for "Inception" (2010), and won a second Academy Award for Best Visual Effects for "Interstellar" (2014).
 He shared the wins with Andrew Lockley, Peter Bebb, and Chris Corbould.
 Franklin has also been nominated for an Academy Award for "The Dark Knight" (2008).
 He was nominated for BAFTA Awards for "Batman Begins", "The Dark Knight" (2008), and "The Dark Knight Rises" (2012).
Dead & Buried is a 1981 science fiction horror film directed by Gary Sherman, starring Melody Anderson, Jack Albertson, and James Farentino.
 The film focuses on a small town wherein a few tourists are murdered, but their corpses begin to reanimate.
 With a screenplay written by Dan O'Bannon and Ronald Shusett, the movie was initially banned as a "video nasty" in the UK in the early 1980s, but was later acquitted of obscenity charges and removed from the Director of Public Prosecutions' list.
Gregory S. Butler (August 18, 1971, Suffield, Connecticut) is a visual effects supervisor.
 He graduated from Suffield High School in 1989 and afterwards entered Hampshire College.
 Despite his initial plans to study history, a work-study job with the audiovisual equipment in the library made him interested in film production.
 Butler graduated in 1993 with a major in film, television and theater design.
 Afterwards he moved to California to work for Industrial Light and Magic for 9 months, where after intern work he managed to become an assistant in the effects department, starting with assistant credits in "The Mask" and "Forrest Gump".
 Following a job at Rocket Science Games until the company's bankruptcy in 1996, Butler went to Tippett Studio and did effects work in "Starship Troopers" and "My Favorite Martian", rising up to a technical director job, and Cinesite for "Practical Magic".
 While reluctant at the requirement of moving to New Zealand, Butler was convinced by his writer-actor brother Jared to jump at the opportunity of working for Weta Digital in "The Lord of the Rings".
 His biggest achievement was working in the creation of Gollum.
 Butler also worked as a computer graphics supervisor on "I, Robot" before an invitation to work as an effects supervisor for the Moving Picture Company, in London.
 He continues on MPC, but is now on the Vancouver office.
 On January 24, 2012, he was nominated for an Academy Award for "".
John Knoll (born October 6, 1962) is an American visual effects supervisor and chief creative officer (CCO) at Industrial Light & Magic (ILM).
 One of the original creators of Adobe Photoshop (along with his brother, Thomas Knoll), he has also worked as visual effects supervisor on the "Star Wars" prequels and the 1997 special editions of the original trilogy.
 He also served as ILM's visual effects supervisor for "Star Trek Generations" and "", as well as the "" series.
 Along with Hal Hickel, Charles Gibson and Allen Hall, Knoll and the trios work on "" earned them the Academy Award for Best Visual Effects.
Nick Allder is an English special effects supervisor and coordinator.
 He started his career as an assistant camera operator and moved, after eight years, into special effects.
 He has won multiple awards, including an Academy Award for Best Visual Effects for the science-fiction horror film "Alien" (1979), and a BAFTA Award for Best Special Visual Effects for the science-fiction film "The Fifth Element" (1997).
 Allder has worked on the set of high-grossing films such as the epic space opera "The Empire Strikes Back" (1980) and the historical drama film "Braveheart" (1995).
Richard Bluff is an English special effects supervisor.
 Known for his works in Disney's visual effects company Industrial Light & Magic (ILM) as a digital matte artist and visual effects supervisor in acclaimed films such as "" (2005), "The Island" (2005), "Transformers" (2007-11), "Indiana Jones and the Kingdom of the Crystal Skull" (2008), "Star Trek" (2009), "Avatar" (2009), "The Avengers" (2012), "Cloud Atlas" (2012) "Pacific Rim" (2013), "The Big Short" (2015) and "Doctor Strange" (2016), for which he received an Academy Award for Best Visual Effects nomination at the 89th Academy Awards.
 He previously worked at Blur Studio as digital artist.
Kaj Steveman (born 1968 in Stockholm) is a Swedish visual effects supervisor.
 He was the Founder and head of Fido Film, one of Sweden's most prominent special effects studios and is most known for his acclaimed work on the Swedish vampire films Let the Right One In and Frostbite.
 He was also visual effects supervisor for and Storm and worked as assistant director in the cult film Evil Ed.
 He worked as a make-up artist on The Hunters.