Underfist: Halloween Bash (otherwise known as Underfist) is an American animated spin-off special of "The Grim Adventures of Billy & Mandy".
 It aired on October 12, 2008.
 The special was going to be the setup for a new series spin-off of "Grim & Evil", but the contract of Maxwell Atoms with Cartoon Network expired before moving to Disney Channel for the TV series "Fish Hooks" and the special was ultimately the finale of the "Grim Adventures of Billy & Mandy" franchise.
The Theater Television Network was an early American television network founded in 1951.
 The network was not a traditional 1950s television network: unlike the other TV networks that operated at that time, Theater Network programs were not broadcast into homes; instead, they aired at participating movie theaters.
Grim & Evil is an American animated television series created by Maxwell Atoms for Cartoon Network, and the 11th of the network's Cartoon Cartoons.
 It consisted of two segments which were eventually spun off into their own series, "The Grim Adventures of Billy & Mandy" and "Evil Con Carne".
The American animated television series "Evil Con Carne" features a cast of fictional characters created by Maxwell Atoms.
 The series, which originally aired on Cartoon Network from July 11, 2003 to October 22, 2004, follows the brain of a playboy who wants to rule the world with his general Skarr and his lover, Major Doctor Ghastly.
 Since Hector Con Carne is attached to a bear named Boskov, Hector wants to find the rest of his body parts and take over the world.
 Unlike Maxwell Atoms' The Grim Adventures of Billy & Mandy, Evil Con Carne lived a short life with only 13 episodes.
The Grim Adventures of Billy & Mandy (also known as Billy & Mandy) is an American animated television series created by Maxwell Atoms for Cartoon Network, and is the 14th of the network's Cartoon Cartoons (albeit on when it was part of "Grim & Evil", due to the "Cartoon Cartoons" brand being temporarily discontinued earlier in June 2003; the show itself is considered by some to still be a "Cartoon Cartoon" show regardless).
 It follows two children named Billy—a slow-witted boy—and Mandy—the cynical best friend—who, after winning a limbo game to save Billy's pet hamster, gain the mighty Grim Reaper as their best friend in eternal servitude and slavery.
Maxwell Atoms (born January 21, 1973) is an American animator, screenwriter and voice actor.
 Atoms is best known as the creator of the Cartoon Network series "The Grim Adventures of Billy & Mandy".
Bunnicula is an American animated television series from Warner Bros.
 Animation developed by Jessica Borutski, produced by Borutski and Maxwell Atoms, and distributed by Warner Bros.
 Television.
 It premiered on Cartoon Network and Boomerang on February 6, 2016.
 It is loosely based on the children's book series by James Howe and Deborah Howe.
 The show is a dark comedy about a vampire rabbit named Bunnicula who likes carrot juice instead of blood to strengthen up his super abilities in new paranormal adventures.
"Adventure Time" is an American animated television series created by Pendleton Ward for Cartoon Network.
 The series follows the adventures of Finn (voiced by Jeremy Shada), a human boy, and his best friend and adoptive brother Jake (voiced by John DiMaggio), a dog with magical powers to change shape and grow and shrink at will.
 Finn and Jake live in the post-apocalyptic Land of Ooo.
 Throughout the series, they interact with the show's other main characters: Princess Bubblegum (voiced by Hynden Walch), the sovereign of the Candy Kingdom; the Ice King (voiced by Tom Kenny), a demented but largely misunderstood ice wizard; Marceline the Vampire Queen (voiced by Olivia Olson), a thousand-year-old vampire and rock music enthusiast; Lumpy Space Princess (voiced by Ward), a melodramatic and immature princess made out of "irradiated stardust"; BMO (voiced by Niki Yang), a sentient video game console-shaped robot that lives with Finn and Jake; and Flame Princess (voiced by Jessica DiCicco), a flame elemental and ruler of the Fire Kingdom.
 The pilot first aired in 2007, and it was later re-aired on the incubator series "Random!
 Cartoons" on Nicktoons Network.
 The pilot eventually leaked onto the internet and became a cult hit on YouTube.
 After Nickelodeon declined to turn the short into a full-fledged show, Cartoon Network purchased the rights, and "Adventure Time" launched as a series on April 5, 2010.
Greg Eagles (born October 28, 1970) is an American voice actor, writer and producer who is best known for voicing The Grim Reaper in "Grim & Evil" and in its spin-off series "The Grim Adventures of Billy & Mandy", he's also known for voicing various other characters in numerous films, television shows and video games.
Evil Con Carne is an American animated series/spin-off of "Grim & Evil" and sister show of "The Grim Adventures of Billy & Mandy", created by Maxwell Atoms.
 The series first appeared on Cartoon Network during the show "Grim & Evil", along with "The Grim Adventures of Billy & Mandy".
 The two series later became separate programs in 2003.
 While "The Grim Adventures of Billy & Mandy" runs for six seasons, "Evil Con Carne" only runs fourteen episodes and ended on October 22, 2004.
 It was also part of Cartoon Network's series, "Cartoon Cartoons", and is the 15th and final cartoon of the series (albeit on when it was part of "Grim & Evil", due to the "Cartoon Cartoons" brand was temporary discontinued earlier in June 2003; the show itself is considered by some to be a "Cartoon Cartoon" regardless).
 An official series finale, titled "Company Halt", aired on March 16, 2007.

Question: Greg Eagles voiced an American television series by Maxwell Atoms that aired on what television network?
Answer: Cartoon Network