Place butter and the marshmallows in a microwave safe bowl and microwave for about 60 seconds, or until melted and smooth. Stir mixture. Add the salt to the mixture and stir. Add the Cocoa Pebbles to the marshmallow mixture and stir. Spread Cocoa Pebble mixture into a 9×13 pan that has been sprayed with cooking spray. Let the Cocoa Pebble Treats cool completely before moving on to the next step. Using a round cookie cutter, press into the Cocoa Pebble Treats to make the round part of the spider body. Select the colors of Twizzlers you want for the legs and cut 8 legs into 2” pieces. Insert 4 legs into each side of the Cocoa Pebble Treat. With the gel frosting, attach the 2 candy eyes. Use leftover Twizzlers to make a smile or creepy fangs for your spider! Happy Halloween!