On a large tray set out all the cups and set aside for later. Note: Make sure you have plenty of room in your refrigerator to place these trays.
In a very large measuring cup with a spout (or a mixing bowl with a spout) whisk together 1 cup of the boiling water with the purple Jell-O until all the Jell-O is dissolved.
Into the cup or bowl, whisk in ½ cup cold water and ½ cup vodka.
Carefully pour this mixture into all the cups (about a quarter to halfway up.)
Carefully place the tray of cups into the refrigerator for about 30 minutes or until that first layer is set.
When ready, make the orange layer the same way as the grape layer. Whisk together the orange Jell-O with 1 cup boiling water until dissolved then whisk in ½ cup cold water and ½ cup vodka.
Carefully pour this orange Jell-O layer on top of the grape layer in all the cups.
Place the tray of cups back into the refrigerator for 2 hours or until they are set.
Meanwhile make the chocolate spider webs (this part is optional). Place a sheet of parchment paper onto a baking sheet.
In a microwave safe bowl, microwave the chocolate chips in 30 second intervals (stirring after each interval) until melted and smooth.
Transfer the chocolate to a ziptop bag, pushing the chocolate as best as possible to one corner then snip off a tiny part of that corner.
Pipe the spiderwebs onto the parchment paper and let them chill in the fridge to harden.
When ready to serve, top each Jell-O shot with a squirt of whipped cream and a chocolate spider web or some Halloween sprinkles.
Notes
I used 1 ounce cups for this recipe.
These can be made non-alcoholic, see above on how to do that.
These will keep for up to a week in the refrigerator.