Green Slime

Serve soft-set lime gelatin out of a bowl. Don't cut it nicely - slop it out. You may wish to add gummy worms or some red food coloring mixed with chocolate syrup so that the slime appears to harbor blood and worms.

Eyeballs

Make Rice Krispie(tm) Treats. The directions are on the cereal box. Form them into balls, about 1 or 2 inches across. Add a pastel M&M(tm) or other small round candy for the iris and dot the candy with frosting or gel for the pupil

Ghost Hand Punch

Buy some new latex gloves. Wash one out and fill with water. Fasten the hole closed with a twist-tie or rubber band. Freeze it. Float it in your favorite punch before serving