Tiny jellyfish species Irukandji is making headlines in Australia. The cnidarian toxin can cause a life-threatening syndrome.
Not the only jellyfish that can put people's lives in danger. The venom of the sea wasp essentially punctures holes in the skin and then leads to cell death. This causes severe pain and later leads to such scarring. Within a few minutes, the poison can lead to cardiovascular failure. In Australia, very few people are stung by jellyfish every year.