At the other end of the scale to the lion’s mane is this little, critter. Don’t be fooled by its diminutive dimensions though; this jelly can pack a nasty punch! The Irukandji is also a member of the box jellyfish family, so its venom rates as some of the most potent in the animal kingdom. Indeed, its toxicity has been estimated to be 100-times greater than that of a cobra! The severe and wide-ranging effects of its sting have even been recognised as a Unique medical condition: irykandji syndrome.

DANGER FACTOR: Irukandji syndrome can cause headaches, nausea, muscle pain, anxiety and, in extreme cases, it can be fatal.

Bell diameter: 25mm (1in)

Tentacle length: < 1m (3.3ft)