Maddie made this one for Annika…  You could put anything on the paper to be revealed. Maddie drew a treasure map. You could do a matching activity, scavenger hunt…  So, draw up your activity, then cover the paper with packing tape. Paint it with a mixture of 2 parts acrylic paint (silver or gold if you have it) and 1 part dish soap. Let dry. Scratch off and play!