Sea Nettles are a type of Jellyfish that can be found in both the Atlantic and Pacific oceans. The ones in this video are Pacific Sea Nettles from the Georgia Aquarium. They have a bell shaped "head" and long stinging tentacles. These tenticles are covered in nematocysts which help them to capture plankton and small fish. These types of jellies will not kill a human with their sting unless someone is allergic. It will be moderately painful and cause a rash that should be treated immediately with vinegar.