Make up some jelly mixture, and when it's cool but not quite set drop some worm-shaped sweets into it. Alternatively, drop the sweets into drinks to create a witches brew.
Try getting the kids to decorate biscuits (either home-made or shop-bought) with red, black and green icing.
To get older kids oohing and ahing make some giant eyeballs. Use an ice-cream scoop to get perfect spheres of vanilla ice cream, then add a dried cranberry or a raisin pushed down into the ice cream as a pupil and draw wavy lines away from it with red icing to create scary giant eyeballs.
Go back to the lab – mixing up certain coloured juices will create a murky, dark looking drink that still tastes great. Try mixing any red juice, for example a cranberry juice, with cloudy apple for that pond-water effect.
Another fun one for the children – bake some cupcakes and allow the children to decorate them with different devilish colours of butter-cream icing, red, green and black, then finish off with coloured sweeties and coloured syrups.
For adults, try serving a punch-packing scarlet soup. Make up a batch of tomato soup with dried chilli flakes added for impact, then swirl through some crème fraiche. Slice bacon into strips lengthways, fry them and add, along with some chopped tomatoes, to the soup.
Another one for adults – try serving 'shots' of pumpkin soup or scarlet 'blood' soup in test tubes. These look great, if a little scary.
Turn gingerbread men into ghouls by covering them in white icing and using raisins for eyes.