The Blue-Ringed Octopus is an extraordinary marine creature, known for its striking blue and black rings, which appear only when it feels threatened. Despite its small size, it possesses tetrodotoxin, a potent neurotoxin that can paralyze and kill humans in minutes. This venom blocks nerve signals, leading to muscle paralysis and, eventually, respiratory failure. There is no known antidote, so prompt artificial respiration is critical.