You can add dry ice directly to a cocktail with a few precautions. Do not ingest or touch dry ice with bare skin. I always use tongs to grab the dry ice and place a small piece in the serving glass. Once you add the dry ice, it’s very dense and will sink to the bottom. Let your guest know not to ingest the ice. They can either sip from the top until the dry ice melts and stops steaming, or let them know to simply wait it out, about five minutes. Of course, dry ice is completely optional, so if you’d rather not add it to the cocktail, you can skip it. That dark hue is enough to get you in the Halloween spirit.