LOS ANGELES, Oct. 3 (UPI) -- Solar Opposites co-creator Mike McMahon said the show's "Sinister Halloween Scary Opposites Solar Special," premiering Monday on Hulu, benefited from voice actor John Kassir reprising his Crypt Keeper voice.
"He was ready to be as dumb as we can get," McMahon told UPI in a recent Zoom interview.
In the special, aliens Terry (Thomas Middleditch) and Jesse (Mary Mack) befriend a crypt keeper. The crypt keeper makes horror puns like Kassir's Tales from the Crypt host did.
"It's a character that he knows better than anybody," McMahon said. "He was improvising and pitching stuff."
McMahon pointed out that the crypt keeper on Solar Opposites is not the Crypt Keeper. It's a crypt keeper.
McMahon also needed Kassir to speak faster to fit all the dialogue into the half-hour show.
"We had to make him speed up though," McMahon said. "Getting to hear fast John Kassir was really fun."
The animated comedy, now in its third season, with a fourth in the works, stars co-creator Justin Roiland as the voice of Korvo, an alien who arrived on Earth with his partner, Terry, and their clones, Jesse and Yumyulack. Korvo is genuinely scared of Halloween on Earth.
"He's worse than scared," McMahon said. "He's spooked. Everything is spooking the bejesus out of him. He's afraid of candy corn, he's afraid of cotton cobwebbing."
Terry and Jesse, meanwhile, embrace Halloween. Writer-producer Danielle Uhlarik said pairing Terry and Jesse for the Halloween story brought out more humor.
"They like to be silly and mess around together," Uhlarik said. "A really dumb human explosion of a holiday is their wheelhouse."
In addition to the off-brand crypt keeper, Solar Opposites put other recognizable characters in the background of the show. You'll notice Jack Skellington from The Nightmare Before Christmas.
Both Hulu and Nightmare are Disney properties, but McMahon said Solar Opposites does not have free reign to use any Disney character.
"The Disney umbrella prevents us from being struck by rain," McMahon said. "But it also prevents lots of legacy character-damaging rain from emitting from the show."
"Sinister Halloween Scary Opposites" also includes The Great Pumpkin from Charlie Brown's Halloween special. But, writer/producer Josh Bycel said there was one character Disney nixed, and it wasn't even their own character.
"E.T. was in it at one point, but the Disney overlords said no," Bycel said.
McMahon said the Disney management did not explain why they wanted E.T. excluded from the special, but Uhlarik said she understood their reservations.
"You can't mess with ET," Uhlarik said.
While Korvo is hiding and Terry and Jesse enjoy Halloween, Yumulack dies and goes to Hell, which is presented as a black-and-white pit of fire in which only the demons' eyes have the color red.
Uhlarik said the black-and-white sequences were inspired by the Scary Stories to Tell in the Dark books.
"The show is usually so colorful," Uhlarik said. "We want to break a little bit of our traditions."