You are correct about the snake, I assumed that the Blue Ringed Octopus was similar but from the Thaiger article it states
…”The venom of the blue-ringed octopus is called Tetrodotoxin, similar to that of pufferfish. It can be found in the saliva, beak, tentacles, intestine, and ink sacs and directly affects the nervous system, leading to paralysis, respiratory failure, and potentially death.”