Answer:
the boxed jellyfish are little jellyfish but they can be big. there venum is the most deadliest of any jellyfish and can kill and adult in about 15 or less min. to cure it you put viniger on the stung area.
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Box jellyfish are in the phylum, Cnidaria. Recently scientists moved them from within the 'true jellyfish' class, Scyphozoa, into their own class, Cubozoa. Their cylindrical shaped bell is rounded at the top and becomes almost square in cross section at the margin of the bell, giving them an almost cubical, or box-like appearance. Projecting down from each corner of the bell is a short, fat appendage called a pedalium. From one to as many as fifteen tentacles are attached to each of the four pedaliums, resulting in between four and sixty tentacles per jellyfish.
Only twenty species have been identified, most of them recently, because they are particularly difficult to study. They can move quickly, have complex sets of eyes (including lens, corneas, and retinas), and demonstrate in the lab the ability to avoid objects. Genetics and better science technique will probably help identify many new species, especially given their threat to an ever increasing number of humans entering the marine environment. However, not all Cubozoans are a danger to humans.