Living organisms that emit lights called bioluminescent contain either luciferin (a substance that emits light in certain chemical reaction) or luciferase (an enzyme that controls these reactions).

Here are some of the most beautiful living organisms that glow in the dark. (Photos courtesy of Wikipedia)

Sea Pens (Ptilosarcus gurneyi)

Sea pens are colonial marine thought to have a cosmopolitan distribution in tropical and temperate waters worldwide. Sea pens are grouped with the octocorals (“soft corals”), together with sea whips and sea feathers.

Pillar Corals (Dendrogyra cylindricus)

Pillar corals are a type of hard coral which live in the western Atlantic Ocean. They are one of the digitate corals which resemble fingers, or a cluster of cigars growing up from the sea floor, but without any secondary branching. Pillars also look like tall towers.

Crystal Jelly (Aequorea Victoria)

Crystal jelly is a bioluminescent jellyfish that is found off the west coast of North America.

Spanish Shawl (Flabellina Iodinea)

Spanish shawl is a species of aolid nudibranch, a very colorful sea slug. This is a marine gastropod mollusk in the family Flabellinidae.

European Lobster (Homarus Gammarus)

European lobster is a large clawed lobster. It is difficult to distinguish from the American lobster (Homarus americanus) – the best distinction is the geographical location, with the European lobster in the eastern Atlantic Ocean and the American lobster in the western Atlantic, and by the lack of teeth on the underside of the rostrum of a European lobster .An easier distinction is that American lobsters are brown when uncooked and European ones are blue. Both are red when cooked.

Antarctic Krill (Euphausia Superba)

Antarctic krill is a species of krill found in the Atlantic waters of the Southern Ocean. Antarctic krill are shrimp-like invertebrates that live in large schools, called swarms, sometimes reaching densities of 10,000-30,000 individual animals per cubic meter.

Ghost Fungus (Omphalotus Nidiformis)

Ghost fungus is a gilled basidiomycete mushroom found in southern Australia most notable for its bioluminescent properties. Generally found growing on dead or dying trees, it is saprotroph and parasite. Foxfire is the term for the bioluminescence created in the right conditions by a few species of fungi that decay wood.