For years, bars including Chicago's Aviary have been serving drinks inside hollow ice balls. The procedure to make one is easy, at least in theory.
Freeze a balloon or an ice ball mold filled with water for a few hours. An ice shell will form on the outside.
Poke a hole in the ice ball and dump out the water. Refill with a (very well chilled) cocktail. Some bars do with a syringe so that you don't have to open a real hole in the ice ball.
Then serve it. I did this at home and thought it would be fun/funny to create Fire Inside Ice - so I filled by ice ball with Fireball cinnamon whiskey.
Then for a bit of a show I filmed dropping it in slow motion. Enjoy.