Choose a container that can hold at least 4 cups of liquid. It should be completely straight all the way up or have a slightly wider top than the bottom. Try to get a container as tall as it is wide and preferably even taller, otherwise the jello won’t fill the straws high enough. Extend each of the straws and pack the straws in as tightly as you can, adding more straws as needed to get a tight fit. Make sure that each straw is flush with the bottom of the container and that the bendable neck part (even though it is completely extended) is facing down. If your container is slightly wider on top than it is on the bottom, it may help, once the straws are packed tightly in, to rubberband the top of the straws to help when pouring in the jello.
In a medium, heat safe mixing bowl, preferably with a pourable edge, stir together plain and flavored gelatin powders. Pour the boiling water over the gelatin, stirring until it is fully dissolved. Allow the gelatin to cool for about 15 minutes, until it is slightly warm but not beginning to set. Stir in the whipping cream. Stir in the green food coloring until you get the desired color. You can see my worms were more gray than brown and I think I added about 10 drops of green food coloring so you may need to play around with the colors a bit, possibly adding a few drops of red or some other color.
Place your container of straws in a larger dish to catch any possible spills. With your container of straws prepped, gently pour the jello mixture over the straws. Don’t worry as you see the jello seeping up the sides of the container. If your straws are tightly packed in and flush with the bottom, they will still fill with jello.
Chill the jello straws for at least 8 hours. When the jello is set, remove the container from the refrigerator and run the sides under warm water until you can pull the straws and jello blob out of the container. This is the messy part – gently extract each straw from the mess and holding the top of the straw tightly with one thumb and forefinger, use the other thumb and forefinger to tightly apply pressure down the entire length of the straw thereby propelling the jiggly little worm from the straw.
Place the jello worms on a baking tray lined with wax paper and refrigerate until ready to serve. Serve in a chilled bowl.