Season 4 begins when five teams are presented with the challenge of creating a terrifying haunted farm.
The four remaining teams are given the challenge of creating a foreboding forest. Film producer Adi Shankar is the guest judge.
The three remaining teams must depict an epic battle between mummies and werewolves, in a challenge featuring guest judge Francia Raisa.
Season 4 comes to a close as the final two teams compete to create terrifying Halloween-themed displays that capture the twisted, demonic world of a haunted carnival.