I love coral, but man are they freaking weird. To start off, they look like some sort of funky alien plant, but they’re actually animal colonies. There’s also very little consistency in how they’re shaped. They’re tall, short, fat, thin, spiky, smooth, colorful, bland, and everything in between.

But just how weird can coral get? Today, we’re going to dive into the top five weirdest coral species.

Cirrhipathes, the Wire Coral

Most people think of coral as these bulbous, sometimes spiky masses that grow outward in all directions. The snaky coral Cirrhipathes, on the other hand, has places to go and things to see. This wiry coral will slowly spiral outward into your aquarium, uncoiling in bizarre patterns like some sort of eel or aquatic snake. There are 16 species within the Cirrhipathes genus, but the Cirrhipathes spiralis is the only one that’s popular in the aquascaping hobby. Fortunately for aquascaping fans, Cirrhipathes spiralis comes in a huge variety of colors, from warm reds and yellows to cool blues and greys.

Wire Coral in a Reef Tank

Image source: Melevsreef.com

Light Bulb Tunicate

Technically, these little critters are sea squirts (not coral), but they’re visually close enough that we can include them on the list anyway. These transparent creatures show off their internal organs and they are capable of bioluminescence, hence their name. It doesn’t get much weirder than glowing guts and transparent skin. Can you imagine using your glowing intestines as a nightlight whenever you wake up in the middle of the night?

Light Bulb Sea Squirt

Image source: smashinglists.com

Feather Coral

I can see why this coral earned the descriptor “feather” with its long, frilly stems. What I love so much about this coral is that it looks almost exactly like some sort of oddly colored fern or jungle plant. The feathery tendrils gently sway in the current the same way that a plant’s leaves move in the wind.

Feather Star Coral

Image source: Messersmith.name

Mushroom Coral

Despite its rather uninteresting name, the mushroom coral is one of the most beautiful creatures that the ocean has to offer. Its beauty is in contrast to its amusingly silly feeding strategy. The mushroom coral simply points its giant mount-like orifice into the current and waits for jellyfish to randomly blunder into the opening. The coral then attacks the jellyfish with stinging tentacles and shoves the jellyfish down its gullet. It’s amazing that such a ridiculous eating style actually works — that’s kind of like and adult tiger sitting around with his mouth open as he waits for rabbits and other small animals to randomly hop onto his tongue.

Technicolor Mushroom Coral

Image source: Ocean.nationalgeographic.com

Veretillum Sea Pen

Kind of reminds you of those dandelion tufts that you used to blow as a child, doesn’t it?

Veretillum Sea Pen

Image source: Livescience.com

Unfortunately, this bizarre species of coral probably won’t function very well as the centerpiece of your aquascape. This nocturnal coral only unfurls its polyps at night. During the day it kind of looks like a moldy hot dog.