Make cake as directed on box. Let cool and cut into cubes.
Make pudding by mixing pudding mixes and milk. Add half the Cool Whip and mix well. Set aside.
Add half the cake cubes to the bottom of the trifle dish and add half the crushed Oreos. Spread on half the pudding cream mixture and repeat layers.
Top with remaining Cool Whip.
Carefully add Hershey's Syrup to the top starting in the middle and swirl around in circles until you get to the edges.
Using a toothpick, draw out lines from the center to create syrup web. Add spider.