You are here: Home › DIY › Can do this one at the beach!.. Take your bag of plaster of paris, mix with sea water. Make depression in damp sand. Put in dead critters, shells, etc. faced toward the bottom. Pour plaster. Let dry and dig around it carefull to remove. Can use irregular shape or press a pail or dish into sand. Can even make sand castles with decorations. They last a long time as garden decor.