Stings from some species, including Chironex fleckeri, Carukia barnesi, Malo kingi, and a few others, are extremely painful and often fatal to humans.

[3] Historically, cubozoans were classified as an order of Scyphozoa until 1973, when they were put in their own class due to their unique biological cycle (lack of strobilation) and morphology.

[10][better source needed] Class Cubozoa The medusa form of a box jellyfish has a squarish, box-like bell, from which its name is derived.

The margins of the septa bear bundles of small gastric filaments which house nematocysts and digestive glands and help to subdue prey.

They possess a ring nerve at the base of the bell that coordinates their pulsing movements, a feature found elsewhere only in the crown jellyfish.

In species such as Tripedalia cystophora, the upper lens eye is used to navigate to their preferred habitats at the edges of mangrove lagoons by observing the direction of the tree canopy.

Research has shown that the minimum visual angle for obstacles avoided by their lower lens eyes matches the half-widths of their receptive fields.

[17] Research indicates that, owing to the number of rhopalial nerve cells and their overall arrangement, visual processing and integration at least partly happen within the rhopalia of box jellyfish.

Discovered and named after scientist Lisa-ann Gershwin, this new species of box jellyfish, Gershwinia thailandensis, is a member of the Carukiidae family.

Gershwinia thailandensis is described as its own new species as it has sensory structures with specialized horns and lacks a common digestive system among box jelly, the stomach gastric phaecellae.

[29] Understanding the ecological distribution of cubozoans can be difficult work, and some of the costly methods like visual observations, a variety of different nets, light attraction techniques, and most recently the use of drones have had some levels of success in locating and tracking different species of cubozoa, but are limited by both anthropogenic and environmental factors.

[29][31] This relatively easy and cost-effective method utilizes extra-organismal genetic material that can be found in the water column via shedding throughout the lifespan of an organism.

[31] The utilization of eDNA can provide a cost-effective and efficient way to monitor populations of box jellyfish in both medusa and polyp life stages, to then use the data to help understand more about their ecology and limit the effects on coastal anthropogenic activities.

[29] It has been found that the statoliths, which are composed of calcium sulfate hemihydrate, exhibit clear sequential incremental layers, thought to be laid down on a daily basis.

[4] The majority of box jellyfishes feed by extending their tentacles and accelerating for a short time upwards, then turn upside-down and stop pulsating.

[34] Alternatively, in July 2023, the box jelly species Chiropsalmus quadrumanus, were found to potentially have iteroparous reproduction, meaning they reproduce multiple times in their life.

[42] In Australia, fatalities are most often caused by the largest species of this class of jellyfish, Chironex fleckeri, one of the world's most venomous creatures.

[52] Nevertheless, most victims do survive, and out of 62 people treated for Irukandji envenomation in Australia in 1996, almost half could be discharged home with few or no symptoms after 6 hours, and only two remained hospitalized approximately a day after they were stung.

In Hawaii, box jellyfish numbers peak approximately seven to ten days after a full moon, when they come near the shore to spawn.

In the Philippines, an estimated 20–40 people die annually from Chirodropid stings, probably owing to limited access to medical facilities and antivenom.

[56] Wearing pantyhose, full body lycra suits, dive skins, or wetsuits is an effective protection against box jellyfish stings.

Removal of tentacles may cause unfired nematocysts to come into contact with the skin and fire, resulting in a greater degree of envenomation.

[citation needed] Although commonly recommended in folklore and even some papers on sting treatment,[63] there is no scientific evidence that urine, ammonia, meat tenderizer, sodium bicarbonate, boric acid, lemon juice, fresh water, steroid cream, alcohol, cold packs, papaya, or hydrogen peroxide will disable further stinging, and these substances may even hasten the release of venom.

[66][67][68][69] In 2011, researchers at the University of Hawaii announced that they had developed an effective treatment against the stings of Hawaiian box jellyfish by "deconstructing" the venom contained in their tentacles.

[70] Its effectiveness was demonstrated in the PBS Nova episode "Venom: Nature's Killer", originally shown on North American television in February 2012.

A cream containing copper gluconate has been produced, to be applied to inhibit the injected venom; although it is used by U.S. military divers, evidence that it is effective in humans is only anecdotal.

[74] In April 2019, a team of researchers at the University of Sydney announced that they had found a possible antidote to Chironex fleckeri venom that would stop pain and skin necrosis if administered within 15 minutes of being stung.

The research showed the therapeutic use of existing drugs targeting cholesterol in mice, although the efficacy of the approach had not been demonstrated in humans.