Print the Halloween pictures and cut them out. You don’t have to cut them out perfectly because a little extra edge on each picture actually helps.
Place the pictures inside the zip lock bag making sure they aren’t on top of each other or overlapping. No need to zip the bag shut because any air that is in the bag will make it difficult.
Using matching colors of glow in the dark puffy paint, “color in” the Halloween pictures on top of the bag, making sure that the different colors connect so that the window cling dries in one piece. Puffy paint is, well, puffy (ha!) but if you apply too much while you are coloring in the Halloween shapes making it extra thick, it will have a hard time drying.
Set the wet window clings aside in a safe place and wait at least 24 hours for the clings to dry.
Once they are dry, carefully peel them off of the plastic bag and place them on a clean window (be sure to clean the window first!).
As the sun sets, the window clings will glow!