Boiling Witches' Brew
Dry ice (available in most supermarkets)
Frozen mugs for root beer
Baileys Irish Cream
Break up the dry ice using gloves (never with your bare hands) and with an ice pick — place a few pieces of the cut-up ice in a "cauldron." Cover the dry ice with water, and place a chilled bowl within the cauldron, on top of the ice. Fill the inner bowl with root beer and put a scoop of ice cream in each mug. Spike with Baileys Irish Cream, if needed.