These are the stinging tentacles of a small Indo-Pacific Portuguese Man of War that washed into shallow water during rough weather. Sometimes during storms, thousands of them get beached by the wind and waves. Despite being poisonous, they are quite beautiful. They are semi-transparent, and often range from light blue to dark purple. They live on the surface of the water with an inflated sail above the water and long underwater tentacles that sting and immobilize small prey. Their poison is a rather nasty neurotoxin. Photographing them was challenging because their tentacles are constantly moving in the water and I was trying not to get stung.