The main premise of this episode it's about a lot of deceased villains from previous episodes coming back for revenge against the park crew.
On the park side, aside of the protagonists and recurrent characters like Death, Gary and the Guardians of Eternal Youth, we have:
- Techmo, from Skips vs. Technology.
- The God of Basketball, from Slam Dunk.
- Lemon Chef, from Just Set Up the Chairs.
- The Baby Ducks, from A Bunch Of Baby Ducks.
And then there's the villains side with a lot of members, led by Garret Bobby Ferguson Jr., and includes:
- Garret Bobby Ferguson, from High Score.
- Howard Fightington and the Zombies from Grave Sights.
- The Night Owl from The Night Owl.
- The Urge from Trash Boat.
- The Hot Dogs from Meat Your Maker.
- The Hammer, from Rage Against the TV.
- The Master Prank Caller, from Prank Callers.
- The Blonde Men from Bet to Be Blonde.
- The Destroyer of Worlds from Just Set Up the Chairs.
- Susan, from Benson Be Gone.
- Broseph Chillaxton, from Cool Bikes.
- The Game Store Manager, from But I Have A Receipt.
- Party Pete, from Party Pete.
- Stag-Man, from Camping Can Be Cool.
- The No Rules Man from House Rules.
- The Summertime Song from This Is My Jam.
- The Duck Collector from A Bunch Of Baby Ducks.
- Skull Punch, from Terror Tales of the Park.
Also, there are other references to previous episodes:
- At the beginning, Mordecai and Rigby use a time machine to escape from GBF Jr., similar to the time machine from Bad Kiss.
- When Skips is attacking Mordecai and Rigby, the latter tells to Skips that they know why he has that name, since he tell them in Diary.
- When the park crew members recover their memories, a few flashbacks from previous episodes triggers on their minds.
