Tree Anemone - Actinodendron arboreum

"Actinodendron arboreum" is a species of sea anemone in the family Actinodendronidae. It is native to the Indo-Pacific where it grows at depths of down to 28 metres. Most sea anemone species are harmless to humans, but "A. arboreum" is highly venomous and its sting can cause severe skin ulcers.