Milo has a decommissioned trailer truck souped up into a haunted attraction called the Scream-a-Torium for Halloween, and has invited his friends and sister for a visit. This includes Zack, who reveals he doesn't get scared of Halloween anymore. Meanwhile, Dakota and Cavendish realize it's the last Halloween ever and decide to have a little Halloween fun.
- Been There, Shaped History: Cavendish and Dakota's actions in this episode inadvertently create the leap year.
- Cowardly Lion: Averted with Zack. For someone that is afraid of fish and is claustro-avoidant, it's surprising to hear that he no longer gets scared so easily on Halloween anymore... until Zack discovers the Scream-a-Torium is dangling on a cliff.
- Fish out of Temporal Water: Cavendish and Dakota are from a future where there is no Halloween, so they are not familiar with the holiday and needed it explained to them.
- Overly Long Gag: The truck drives into a lot of warehouses after it has rolled away, including an empty warehouse.
- Shout-Out: During Dakota's song, the time traveling duo are dressed up as Phineas and Ferb for a brief moment. Earlier, they encounter a kid dressed like Perry the Platypus as well.
- Side Bet: Subverted. Zack tries to start one, but Melissa cuts him off, saying it's not gonna happen this time.
- Sticky Fingers: As usual, Dakota can't keep his hands off of Brick and Savannah's belongings.