In a large bowl, beat the sugar, water, oil, eggs, vinegar and vanilla until combined. In a large bowl, combine the flour, cocoa, baking soda and salt; gradually add to egg mixture until blended. Fill paper-lined muffin cups half full.
For filling, in a small bowl, beat cream cheese and sugar until smooth. Beat in the egg, salt and food coloring. Fold in chocolate chips. Drop by heaping tablespoonfuls into the center of each cupcake.
Bake at 350° for 20-25 minutes or until a toothpick inserted into cake part of cupcake comes out clean. Cool for 5 minutes before removing from pans to wire racks to cool completely.
For frosting, in a large bowl, cream butter until light and fluffy. Beat in the confectioners' sugar, vanilla and food coloring. Add enough milk to achieve desired consistency. Frost cupcakes.
Poke shoestring licorice pieces into marshmallows to create antennae; insert into cupcakes. Use candies to decorate alien faces. Store in the refrigerator.