Together, the zooids act as one being and are sometimes seen floating in groups of 1,000 or more.
According to the Fylde Sand Dunes Project, the siphonophores have been washing up on Britain’s shores, sparking an official warning from the group.
The Man O’ War’s tentacles are packed with so-called stinging nematocysts, which are tiny capsules packed with venomous barbed tubes.
These are powerful enough to paralyse or even kill small fish and crustaceans.
According to the US National Ocean Service, the sting is rarely deadly to people but can be incredibly painful and leave behind welts.