Lion's mane jellyfish (Cyanea capillata) envenoming presenting as suspected decompression sickness.

Lion's mane jellyfish stings are usually characterised by local inflammation, especially weals. Systemic symptoms are not widely described although there is a well known fictional description of a fatal reaction to envenoming. We describe five divers presenting with suspected decompression sickness, where the probable diagnosis was jellyfish envenoming.