Add a dash of spooky science to your Halloween decor — with an eerie, oozy chemical concoction you whip up yourself! Put your measuring and color-mixing skills to the test while blending together baking soda, foaming gel, and liquid colors. Pour the mixture into a carved pumpkin from home, add water and citric acid, then sit back as the chemicals react and make your pumpkin “puke”! Barf has never before been such a blast.