This is a much debated topic i thought i might clear up a little, So instead of going out with a bang i'm going in with one. This is my first post and if you would like to, you can address me as jackson. Thank you, and let's get started. All cephalopods have a little bit of numbing poison in them for killing prey, except for a few species of squid. There are multiple species of VENOMOUS octopus that have dangerous potential with their toxins, these species are hapalochaena fascia, lunulata, maculosa, and I don't believe nierstraszi is considered a valid species yet, so I will not include it. These are the blue ringed octopi. They each contain the following ingredients, tetrodotoxin, the main toxin, histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine as well. This causes motor paralysis, and respiratory arrest within minutes of exposure. It is enough to kill at least 11 grown men. Next up is the flamboyant cuttlefish! metasepia pfefferi, My favorite on this list, there is rather little information regarding this species which contains similar toxin to the blue ringed octopus but there has been absolutely NO research done extensively on their biology at the time of this threads writing. If there was I would know about it. the other species in the genus metasepia, is metasepia tullbergi. This cuttlefish contains the majority of the same componets as pfefferi, but contains tetrodotoxin too. The main dividing line between toxins in the blue ring and flamboyant cuttle is that the blue ring can exploit the poison in a bite, metasepia sp. Cannot. They have their poisons located in their body, preventing them from being eaten. This upcoming news is what will be shocking. Sepia bandensis and officinalis both contain tetrodotoxin! It is located in the brain, heart, and blood. And last but not least, the paper nautilis. Only the female contains the toxin, as well as being visibly different from the male as well. Even the worlds top scientists haven't the slightest idea what is in the poison! So don't ask me. If you have any questions or I got something wrong, please post below.