Irukandji jellyfish ( ) are small and the most venomous box jellyfish in the world, that inhabits marine waters of Australia and which are able to fire their stingers into their victim, causing symptoms collectively known as Irukandji syndrome. Their size is roughly a cubic centimetre (1 cm³). There are five known species of Irukandji: Carukia barnesi, Malo kingi and discovered in the 2000s and 2010s, Malo maximus, Malo filipina and Malo bella.