Box Jellyfish

The box jellyfish is a near-invisible, cube-shaped medusa with tentacles trailing from each corner, drifting in Indo-Pacific coastal waters during warm months. Despite its soft appearance, it ranks among the ocean's most venomous animals; its nematocysts deliver toxins potent enough to cause severe stings and, rarely, fatal reactions in humans. Divers in tropical Australian and Southeast Asian waters during summer should exercise extreme caution in shallow, murky areas where box jellyfish congregate, and wear protective suits or wetsuits to minimize skin exposure.