Take a teaspoon or so of black paste for food and stir it into any basic sugar cookie recipe. The dough will turn a rich black that's perfect for making bat cookies. Regular green food coloring does nice things to Halloween Jello. Make a bowl of orange jello and when it's semi-solid drip several drops of green coloring onto the surface and stir them in gently. They'll swirl into dark demonic tornado clouds a dab of back whipped cream made by adding more of that black paste to partially whipped cream makes a pleasantly disgusting finishing touch. Scrambled eggs feel and look much more like brains than cold spaghetti add a few drops of green, red and blue food coloring as you're beating the eggs and the final product will frighten even the most hardened child. A drop of two of red coloring turn grapefruit sections pale pink making them into very convincing thumbs. Drop a pint of cherry tomatoes into a pot of boiling water, blanch them for a minute and then drain and slip off their skins. Instant bloody eyeballs. If you stir baking soda into vinegar, it'll foam right out of the glass. You can also shake salt over a lighted jack o lantern candle and make blue sparks.