Heat oven to 350°F. Line cupcake pan with liners (makes 24).
Stir together sugar, flour, cocoa, baking powder, baking soda and salt in large bowl. Add eggs, milk, oil and vanilla; beat on medium speed of mixer 2 minutes.
Carefully stir in boiling water. Fill each cupcake liner 2/3 full.
Bake 22 to 25 minutes for cupcakes or until toothpick inserted in center comes out clean.
For the Frosting:
Cream butter in electric mixer fit with paddle attachment for 2 minutes.
Add powdered sugar to butter 1 cup at a time, beating well after each addition.
Add vanilla and milk and beat for 2 minutes.
If you want a thicker consistency, add more powdered sugar.
Pipe onto cooled cupcakes.
For the Web:
Loosely set cotton candy on top of white frosting. Garnish with spiders!
I have received a few questions about cotton candy not holding up. So mine did just fine for about an hour but if you live in a really humid area, it might be less. Set the cotton candy on the cupcakes just before serving for best results!