Mauve stinger
This fairly small jellyfish (bell diameter of 3–12 cm) pack a powerful punch in their sting.
Their colour is variable, ranging from mauve, purple, pink, light brown to yellow. The body is radially symmetrical. There is only one body cavity known as the gastrovascular cavity. This is a primitive gut or digestive cavity with only one opening that is used for ingestion and excretion; there are four long oral arms Each medusa has eight long tentacles that emerge from the umbrella margin.
Mauve stingers are bioluminescent, that is they have an ability to produce a low light that is visible to humans during the night. Light is emitted in the form of flashes when the medusa is stimulated by turbulence created by waves or by a ship's motion.
Besides stingers on its tentacles, the mauve stinger also has stinging cells on the bell head which is very unusual.
The sting causes pain that typically lasts 1–2 weeks, local redness, swelling and a rash, but it is generally not dangerous and there are no known fatalities.