They started their 30-Hour Coffin Challenge on Sunday, set to conclude Monday at 8:30 p.m.
Those who survive until that time will be greeted with a "Raising from the Dead Ceremony" with emcee Butch Patrick, who starred as Eddie in "The Munsters."
To complete the challenge, participants needed to lie in a fully-covered coffin with a lid containing just a small mesh hole for that ultra-claustrophobic feeling.
They have to take part in games that include live bugs and pungent food items, and they can also answer trivia to earn points, penalties and a "Get Out of the Coffin" card.
There are fewer bathroom, stretch and phone breaks than in previous years. Coffin dwellers are only permitted to leave the coffin once for 13 minutes every three hours to use the restroom or their phones.
They have to survive sleep deprivation with what is dubbed the "Yacht Rock," as well as listen to songs like "Baby Shark" on repeat during overnight hours.
More than 6,000 applications were accepted from individuals and pairs who wanted to conquer the event together. Contestants had to eat all of their meals in the coffin and endure surprise visits from Fright Fest freaks and live critters like snakes, spiders and skunks.
Scores will be tabulated throughout the event, and the grand prize winner will receive $600, two Six Flags Gold Passes and two Fright Fest Haunted Maze Passes.
Runners up will receive items ranging from Fright Fest day passes to season passes.