blue ringed octopus

The blue-ringed octopus is currently one of the most dangerous known sea creatures and, despite its small size, carries enough venom to kill 26 adult humans within minutes. Furthermore, their bites are tiny and often painless, with many victims not realizing they have been envenomated until respiratory depression and paralysis start to set in.
First you will feel nauseous. Your vision becomes hazy. Within seconds you are blind. You lose your sense of touch. You cannot speak or swallow. Three minutes later you are paralysed and unable to breath.