Question: Who sometimes known under the pseudonym "Designer X",  Callie Thorne or Greg Costikyan ?

Context paragraphs:
The Creature That Ate Sheboygan: The Creature That Ate Sheboygan is a science fiction board game released in 1979 by Simulations Publications (SPI).  The game was originally designed by Greg Costikyan.  It won the Charles S. Roberts Award for "Best Fantasy or Science Fiction Game of 1979".  The game is very similar to the Epyx 1981 release, "Crush, Crumble and Chomp! ".

Ed's Next Move: Ed's Next Move is a 1996 American romantic comedy film written and directed by John C. Walsh.  It stars Matt Ross and Callie Thorne.  A micro-budget romantic comedy about a transplanted Midwesterner adapting to life in New York's East Village, the film appeared at the 1996 Sundance Film Festival where it received critical praise and was picked up by Orion Classics for theatrical release.  The LA Times' Kenneth Turan called the movie "one of the most appealing, audience friendly films at Sundance," while Roger Ebert referred to the film as "a truth telling comedy with quiet wit and bright dialogue. "  Sight & Sound called it "a perfectly formed romantic comedy."

Callie Thorne: Calliope "Callie" Thorne (born November 20, 1969) is an American actress known for her role as Dr. Dani Santino on the USA Network series "Necessary Roughness".  She is also known for past work such as her roles on "" as Detective Laura Ballard, a role she held for two seasons, and the movie "", as well as for playing Sheila Keefe on "Rescue Me" and Elena McNulty in "The Wire".

List of Necessary Roughness episodes: "Necessary Roughness" is a USA Network drama which premiered on June 29, 2011.  The series stars Callie Thorne as Danielle Santino, a tough Long Island divorcee who, in order to make ends meet, gets a job as a therapist for a professional football team.

Greg Costikyan: Greg Costikyan (born July 22, 1959, in New York City), sometimes known under the pseudonym "Designer X", is an American game designer and science fiction writer.

Necessary Roughness (TV series): Necessary Roughness is a USA Network television series starring Callie Thorne and Scott Cohen that aired from June 29, 2011 to August 21, 2013.  The second season premiered on June 6, 2012.  The one-hour drama series was picked up for 12 episodes on January 19, 2011.  On January 7, 2013, USA Network announced the series was renewed for a 10-episode third season, which began on June 12, 2013.  On November 19, 2013, USA canceled the series after three seasons.

Paranoia (role-playing game): Paranoia is a dystopian science-fiction tabletop role-playing game originally designed and written by Greg Costikyan, Dan Gelber, and Eric Goldberg, and first published in 1984 by West End Games.  Since 2004 the game has been published under license by Mongoose Publishing.  The game won the Origins Award for Best Roleplaying Rules of 1984 and was inducted into the Origins Awards Hall of Fame in 2007.  "Paranoia" is notable among tabletop games for being more competitive than co-operative, with players encouraged to betray one another for their own interests, as well as for keeping a light-hearted, tongue in cheek tone despite its dystopian setting.

Violence (role-playing game): Violence: The Role-Playing Game of Egregious and Repulsive Bloodshed is a short, 32-page role-playing game written by Greg Costikyan under the pseudonym "Designer X" and published by Hogshead Publishing in 1999 as part of its "New Style" line of games.

MadMaze: MadMaze is an online video game designed by Eric Goldberg and developed by Greg Costikyan in 1989.  It was the first online game to draw over a million players., and was playable through the Prodigy service.  The game disappeared in 1999 with the death of the Prodigy service, but with the permission from the service and the creators, fans of the game have rehosted it.

Laura Ballard: Laura Ballard is a fictional character in "", played by Callie Thorne.  She is a police detective in the homicide division of the Baltimore Police Department.

Supporting paragraphs: Callie Thorne Greg Costikyan
Answer: Greg Costikyan