Isaac creates a "nest" for himself every night at bed time. He gets in the middle of his full-size mattress and surrounds himself with sleep toys -- literally surrounds himself, making a "U" of stuffies that he puts himself in the center of. Then he asks me to cover him all the way, so that not even his head pokes out. This makes him feel safe.
Isaac isn't scared of the usual under-the-bed or hiding-in-the-closet monsters. Nope. His most recent after the lights go out obsession was Medusa. The one from the original, Harry Hamlin "Clash of the Titans." Bears and robots have also been of concern in the past. I'll take a bear over Medusa any day.
I tried using Go Away, Big Green Monster! by Ed Emberly to help alleviate some of his fears and give him some sense of control over them. It didn't have much success, but it did become one of his favorite books.
In this book, Emberly, in his trademark minimalistic style, employs a dark background, bright colors and page cut-outs to create a Big Green Monster with each turn of the page. Once the Monster is created, the reader slowly dismantles it, removing its hair, ears, nose, face, mouth, teeth, and eyes until telling it to "Go Away and Don't Come Back," with the caveat "until I say so!"
I have used this book with kids a lot and they love participating in sending the monster away with the loudest send off possible. Isaac loves it, too. He laughs as the monster devolves as the pages turn and gives him a loud farewell. And, though the book hasn't helped him completely send his monsters away, he has found his own method of controlling his fears and keeping them at bay.