‘The Simpsons’ Joins Extremely Rare 600 Episode Club

The only other member is “Gunsmoke”

The Simpsons Treehouse of Horror Halloween 600 episode
From "Treehouse of Horror XXVII" (Fox)

As tonight’s episode of Fox’s long-running animated series “The Simpsons” airs, it will join a rarified group.

Titled “Treehouse of Horror XXVII,” the show marks the 600th episode of the 27-year-old series.

One for the history books in more ways than one, tonight’s episode also marks the 27th annual “Simpsons” Halloween special.

Sunday’s show will feature the children of Springfield fight to the death for one day in Mr. Burns’ personal reservoir — an apparent spoof on the popular horror movie series “The Purge.” Viewers can also catch Lisa’s imaginary friend kill her real friends, as Moe recruits Bart into his group of covert barfly agents.

The only other primetime series to surpass 600 episodes is “Gunsmoke,” which aired from 1955 to 1975. The Western series starring James Arness, Milburn Stone and Amanda Blake holds the record for the most episodes with 635.

At that rate, “The Simpsons” won’t be break that record until 2018. That is, assuming it remains on the air.

“The Simpsons” already has “Gunsmoke” beat on season count: The CBS Western aired for 20 seasons while Fox’s animated series has been televised for 28 seasons — the most by far of any primetime show.

Sunday’s episode will acknowledge the “#600” milestone during the opening and closing segments.

The episode will play out like every other “Treehouse of Horror” installment, according to an IGN review. “That means three segments that pay lip service to the Halloween theme, spoof various popular movies and feature far more death and violence than you’ll find on an average episode of the show,” wrote an IGN critic, who also warned: “Outside of the opening, there’s very little about this episode that actually screams ‘Halloween.’ But that’s been the general trend in recent years, so if disappointing, the lack of Halloween elements is hardly surprising at this point.”