Australian Brett Wallensky discovered a dense mat of bluebottles washed up on the rocks, south of Batemans Bay, Australia. / Brett Wallensky Facebook Photo

Bluebottles are siphonophores, a strange kind of colonial jellyfish. Rather than being a single organism, individuals each make up parts of the colony's tentacles, digestive system and more. Fortunately, Australian bluebottles are less venomous than their northern cousin, the Atlantic Portuguese Man o' War or "floating terror." / Brett Wallensky Facebook Photo

More than 10,000 people report being stung by bluebottles in Australia every year, and that number can climb to 30,000 in peak years. / Brett Wallensky Facebook Photo