Wildlife to Witness: Physalia Utriculus (Blue Bottle)

Locally known as "Sabay", the Blue Bottle (Physalia Utriculus) 

Physalia utriculus, also called Blue Bottle or (Indo-Pacific) Portuguese Man-of-War, is a marine hydrozoan of the order Siphonophora found in the Indian and Pacific oceans. A gas filled bladder allows it to float on the surface, propelled by currents, tides, and by a sail at the top of the bladder, which may be left or right-handed. A single long tentacle of venomous cnidocytes, hanging below the float, provides the animal with a means of capturing prey.
P. utriculus is distinguished from the Atlantic Portuguese Man o' War (Physalia physalis) by the smaller size of the float (six inches compared to twelve) and by having a single long fishing tentacle. Like its larger relative, P. utriculus often occurs in swarms.

Source: wikipedia.com