Physalia physalis: "Portuguese man-of-war" or "blue-bottle". This colony of hydroids floats on the surface of the sea using an air bladder, and is frequently stranded on our beaches. They possess long tentacles that trail below the surface and can be found around South and southern Africa. This species has a painful sting..Plough snails feed on blue bottles by thrusting in long proboscis and sucking up soft tissue. Up to one-third of the snail's mass can be consumed in a single meal. Bullia are immune to the stinging cells of bluebottles.