These beauties are known as deep-sea octorals, or soft corals. Otherwise commonly referred to as mushroom coral (Anthomastus ritte), these cnidarians use stinging cells or nematocysts within their stunningly flashy tentacles in order to catch prey. Deep sea mushroom coral has been found at depths where natural light cannot reach, so photosynthesis could not occur. Since most corals are dependent on this transformation of light into sugar, becoming predators has allowed them to flourish where other reefs would wither away. Rather than turning the sunlight into a form of energy they can digest, they instead just eat prey that swims by and turn that into energy.
Photo credit: NOAA, Ocean Explorer