Caulerpa taxifolia

Caulerpa taxifolia is a species of green seaweed, an alga of the genus Caulerpa, native to tropical waters of the Pacific Ocean, LIndian Ocean, and Caribbean Sea. The species name taxifolia arises from the resemblance of its leaf-like fronds to those of the yew (Taxus). A strain of the species bred for use in aquariums has established non-native populations in waters of the Mediterranean Sea, the United States, and Australia.

Quotes

 * As it stands, it's the monster from hell, about which nobody knows what to do.
 * Jeremy Jackson, How we wrecked the ocean (April 2010) Ted