The Twist Ending. The Morris's and Luke get home safely, only to find a horror hitching a ride on the back of the bus. Why? So he can give them free passes for next year, of course!
The Graphic Novel is even better, with the humans having faces that just scream "you have got to be kidding me."
The episode contains examples of:
The TV adaption of One Day At Horrorland really hams up the Horrors, especially when the Morrises are being prepped for the "Raw Deal" TV show.
Horror Make-Up Artist: Darling, we're monsters, but we're not monsters.
And then there's the commercial for Greatest Monster Love Songs. It must be seen to be believed.
There's also the commercial for the human action figures, with the announcer encouraging the kids watching it to torture the toys.