Turn the bowl that will serve as the mold upside down and cover the outside with aluminum foil. Fold excess foil into the interior of the bowl.
Tear the bags or craft paper into roughly 2" to 3" pieces. Pour the Mod Podge into a small disposable bowl. Dip each paper piece into Mod Podge and place on the outside of the foil-covered bowl, overlapping the paper to cover the bowl. TIP: Work with the bowl inverted over a object like a spary paint can so that it is easy to spin. Continue adding paper until 3-4 layers of paper cover the outside of the bowl.
Allow the bowl to dry for 24 hours. When the bowl is dry, gently peel the foil off the inside of the glass bowl, releasing the bowl from the paper shell. Gently peel foil from the paper shell.
Cut the cheesecloth into 3 random shaped pieces. Saturate the pieces with Stiffy and use your fingers to press out any excess Stiffy. Working over wax paper, drape the wet cheesecloth pieces over the bowl, overlap the pieces and crunch the bottoms. Allow to dry 1 hour.
Stain the wood spider web using a foam brush. Let it set for a few minutes and wipe away the excess with a paper towel. Repeat for a darker color if desired. Allow to dry 1 hour.
Add copper glitter paint to the top of the spider web and allow to dry.
Secure the spider web to the center of the bowl with a drop of hot glue.