Original screen used Loki Mask from the hit Jim Carrey film The Mask.
Christopher Gilman, the creator of the Mask props, said that @15-23 were made for the film. Most were resin painted to look like wood, & a few were made of foam to float, and for Milo, the dog, to catch when one was thrown to him. The "L" symbol on the forehead of the mask was slightly changed a few days after filming began.