During the Windows to the Deep 2019 expedition, we encountered this charismatic swimming jelly called a helmet jelly that was twisting and tumbling as it moved across remotely operated vehicle Deep Discoverer’s field of view. With a characteristic groove encircling its swimming bell, the helmet jelly is classified as a coronate scyphomedusa, with a scientific name of Periphylla periphylla. Read more about these jellies in this mission log.