The monster costumes were designed by Bob Verberkmoes, a theater set designer, and constructed at Gutzon Borglum's sculpting studio in Stamford. The costume heads sat atop the actors' heads, such that the actor looked through a hole in the costume neck. Two monster costumes were constructed,; upon completion, one was found to be too small for the hired stuntman/actor. Production assistant Ruth Glassenberg Freedman had a 16 year old son, Charles Freedman, who fit perfectly into the small suit, and he was subsequently recruited to portray a monster(s) in the film. The "underwater," skeleton transformation scene was shot on a stage, with images of tropical fish in an aquarium later superimposed over the dissolving stage shots. Chocolate syrup was used for blood during the monster attack scenes.