Can a blue ringed octopus kill a whale?

No, a blue-ringed octopus cannot kill a whale. Blue-ringed octopuses are small, venomous creatures that primarily prey on small fish and crustaceans. Their venom is potent enough to kill a human, but it is not powerful enough to take down a large marine mammal like a whale. Whales are much larger and have thick blubber that would provide protection against the octopus's venom.