Special equipment: 20 flexible straws and a clean flower pot, optional
Put 3 cups water in a pan, bring to a boil and turn off the heat. Stir in the strawberry and unflavored gelatin until completely dissolved. Stir in the cream. Pour the hot liquid into a bowl and let stand until slightly thickened, 15 to 20 minutes.
Meanwhile, using a tall drinking glass wide enough to hold all the straws, cut out a circle from the slice of bread to fit in the bottom of the glass. Bundle the straws together with a rubber band and stand them up in the glass, pressing the bottom ends into the circle of bread.
Using a spouted measuring cup, pour the gelatin mixture into the tops of the straws. Refrigerate until chilled and set up completely, 1 1/2 to 2 hours.
Put the chocolate wafers in a resealable plastic bag and crush with a rolling pin. Arrange the crushed cookie on a plate or in a cleaned flower pot.
Use the back of a flat wooden spoon to push the gelatin out of the straws. Toss the jelly worms into the crushed cookies, leaving some to stick out.