Terrible pun I know. Still, aren't these creatures just beyond breathtaking? Although many siphonophorae can be mistaken for your average looking jellyfish, this is something else entirely. You almost expect it to casually turn towards the camera and ask for a call home.
Siphonophorae might appear to be a single organism but each specimen is actually a colony composed of many individual animals. Most colonies are long, thin, transparent pelagic floaters.
The best known species is the dangerous Portuguese man o' war (Physalia physalis) . With a body length of 40–50 m (130–160 ft), another species of siphonophore, Praya dubia , is one of the longest animals in the world.
Each zooid (a single animal part of a colonial animal) is an individual, but their integration with each other is so strong, the colony attains the character of one large organism. Indeed, most of the zooids are so specialized, they lack the ability to survive on their own. Siphonophorae thus exist at the boundary between colonial and complex multicellular organisms.
Like other hydrozoans, certain siphonophores can emit light. A siphonophore of the genus Erenna  has been discovered at a depth of around 1,600 m (5,200 ft) off the coast of Monterey, California. The individuals from these colonies are strung together like a feather boa. They prey on small animals using stinging cells. Among the stinging cells are stalks with red glowing ends. The tips twitch back and forth, creating a twinkling effect. Twinkling red lights are thought to attract the small fish eaten by these siphonophores. While many sea animals produce blue and green bioluminescence, this siphonophore was only the second lifeform found to produce a red light (the first being the scaleless dragonfish Chirostomias pliopterus ).
 Portuguese man o' war
 Praya dubia
 Siphonophore of the genus Erenna
 Scaleless Dragonfish
Bonus; Marrus orthocanna
> http://deepseanews.com/2014/06/amazing-purple-jelly-sighting-in-the-deep-sea/ .
Looking for more creatures from the deep?
> Stranger in a Strange land
> Sea Pigs
> Dreaming of Europeans