Silkspanner

The Silkspanner is a flightless dragon first seen in Burning Midnight. Its name however was revealed in Dragonvine in which it will appear again.

Official Description
"This nomatic spider-dragons island hop across the Archipelago by weaving web wings between their six arms and ballooning their gullets with air."

- Dragons: Rise of Berk

Egg
A Silkspanner egg is oval, full of bumps, and has a greenish color. It has several spikes for protection on the upper half. In addition, it is covered in a large web, possibly by the parents.

Hatchling to Adult
The Silkspanner is a six-legged wingless dragon. It has four eyes; a bigger pair and a smaller pair. It has chelicereaes, similar to a spider's. Its body is green with yellow underbelly and light purple legs. It has a row of long sharp spines along its back and a long tail. It has long thin claws and a small membrane between its toes. It has a lot of thin spines on its head and under the chin.

Titan Wing
A Titan Wing Silkspanner is not very different from the adult form. The most noteable change is that there are many more spikes on its back, head and legs. It turn sea blue in color, with pale white belly.

Spitting Webs
As mentioned in the overview of Dragonvine, Silkspanners can create webs, similar to those of a spider, and trap their prey in them.

Climbing
As seen in Burning Midnight, Silkspanners can climb vertical rock walls and trees with their long claws.

Burning Midnight
The Riders, Valka, Gobber, and Eret trap themselves in a cave as protection from wild dragons attacking them so they can rest for a bit. At the end of this comic, when Hiccup and Toothless come out of the cave, it's revealed that the wild dragons are Silkspanners. And they are surrounding the cave.

Dragonvine
Their name and ability was revealed in the overview of this comic. They will later appear in it.

Dragons: Rise of Berk
The Silkspanner was introduced in this game in a Dreadfall update.

Trivia

 * It is the second dragon with more than a pair of eyes, the first being the Red Death.
 * It is the fourth flightless dragon and the second one without wings.
 * It is also the fourth dragon with more than two pairs of legs, the others being the Fireworm, the Hackatoo, and the Thunderpede.
 * It is the third dragon to originate from a comic and the second to be later introduced in Rise of Berk.
 * They're rather obviously inspired by spiders, given that they are flightless, have six legs, have more than two eyes, and spin webs.