Whisk together one cup of boiling water and the yellow jello packet until jello is fully dissolved.
Add ½ cup of vanilla vodka and ½ cup cold water to the jello mixture.
Pour the yellow jello to fill the bottom ⅓ of shot glasses. Recipe will make about 30 jello shots.
Place the shot glasses on a sheet pan for easy transfer to and from the refrigerator. Chill jello shots in the refrigerator for about 1 hour, until set.
Mix together the orange layer exactly as you've mixed the yellow layer - combine boiling water and orange jello until dissolved. Add vodka and cold water.
This time, however, be sure the orange jello liquid is room temperature (not warm) before pouring over the yellow layer. Fill each shot glass with orange jello until ⅔ full. Chill for another hour.
To make the white layer, add 1 cup of boiling water into a bowl and sprinkle both packets of clear gelatin over the water. Whisk well, until gelatin is fully dissolved. Add can of sweetened condensed milk and allow mixture to cool to room temperature. (We did not add vodka to this layer, though you can if you want.)
Pour the white jello mixture to top of the orange layer to finish the shots.
Chill for 1-2 hours more in the refrigerator until the jello shots are set. Top with a candy corn right before serving.