After stinging the tarantula, which paralyzes (although does not kill) it, the Tarantula hawk drags the tarantula off the path to its nest in order to lay an egg on it. Once the egg hatches, the newly emerged tarantula hawk will use the still living (and still paralyzed) tarantula as its own personal buffet, eating around the vital organs to keep the tarantula alive as long as possible. It's like something out of a horror/scifi movie.

This video shows the tarantula hawk dragging off the paralyzed tarantula.

By the way, for humans, while not paralyzing, the sting of the tarantula hawk is said to be one of the most painful stings by an insect.

Video taken around sunset on August 11, 2017 at Irvine Regional Park in Irvine, California.