Nyctophobia.

As Liz struggles with nyctophobia (fear of the dark), a form of anxiety disorder that causes sleeping issues, she desperately tries to fall asleep by entering her “inner world” where she can access her happy childhood memories. However, she ultimately becomes trapped in a time loop of sorts in her “lucid dream” world and encounters her nightmare, Dark Figure, who appears in various forms and shapes as a clown. The time loop pushes her deeper into her lucid dream world, forcing her to reach her subconscious world where she meets her worst nightmare, the original form of Dark Figure.