Silkspanner

The Silkspanner is a flightless dragon that first appeared in Dragonvine.

Official Description
"This nomadic 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 that shares some resemblances with an iguana. It has four eyes; a bigger pair and a smaller pair. It has chelicereaes, similar to a spider's, and 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, as well as long thin claws and a small membrane between its toes. It also possesses numerous thin spines on its head and under its chin.

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

Spitting Silk
Just like spiders, Silkspanners can shoot silk to create webs and trap their prey in them. They can launch these silks from their mouths and their rear ends.

Climbing
Silkspanners can climb vertical rock walls and trees with their long claws.

Wingless Flight
Silkspanners are able to fly and glide for relatively short distances (i.e. between islands, but not across the archipelago) by weaving webbing between their three pairs of legs. With these, they are able to catch the wind currents. This leaves them somewhat vulnerable to the whims of wind direction. Additionally, they fill their stomachs with air to add some buoyancy, according to Dragons: Rise of Berk.

Poison Removal
Baby Silkspanners have demonstrated the ability to suck out the toxic component in Dragonvine infecting both dragons and humans, and do so in a seemingly painless process. It is not divulged if adult Silkspanners can also do this.

Strength
Silkspanners appear to be strong dragons, for the hatchlings are able to use their webbing to grab and lift full-grown humans with minimal effort, and two of them are able to carry Bayana without any signs of struggle.

Dragonvine
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. After a short while, Hiccup and Toothless blast their way out of the cave, revealing that the wild dragons surrounding the cave are Silkspanners. Toothless attempts to assert his dominance, but the Silkspanners are too frenzied to follow his commands. Eventually, the Riders manage to scare off the Silkspanners, but not before Hiccup snatches an arrow that is lodged on one of them. Hiccup believed that the Silkspanners had encountered the Dragon Hunters, which caused them to become hostile towards humans.

Some of the Riders begin to search for the Silkspanners as they come across an island where the Silkspanners originate from, one that is infested with the deadly dragonvine plant. It is revealed that Bayana and his tribe drove the Silkspanners from the island in order to grow dragonvine to defend themselves. As the Riders continue their search, Hiccup and Gobber conclude that the Silkspanners need heavy gusts of wind to help in their journey, and it is not long for them to come across an island that has become the nest of a female Silkspanner and her hatchlings. The Riders begin to fend off the attack, but Toothless is unknowingly ambushed by a dragonvine that was secretly placed in his saddle by Bayana. Before Hiccup can fight off the approaching Silkspanners, Fishlegs and Valka arrive on Cloudjumper to leave the dragons be, for their purpose is to feed on the dragonvine and free Toothless in the process.

Hiccup and the Riders then return to the island where dragonvine is continuously sprouting out of control and allow the Silkspanners to feed on them, preventing the plant from spreading to other islands. Upon this realization, Bayana and his tribe decide to coexist with the Silkspanners.

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

Trivia

 * Bayana and his tribesmen refer to the Silkspanners as 'Anansi'. Anansi is a character in mythology that is sometimes a man and sometimes a spider or a mix of both, and represents wisdom. Anansi figures into the Akan culture occupying the Gold Coast region in Africa, in what is present-day Ghana.
 * The Silkspanner is the second dragon that possesses more than one pair of eyes, with the first being the Red Death.
 * The Silkspanner is the fourth flightless dragon and the second one without wings.
 * The Silkspanner is the first flightless dragon that is able to glide.
 * The Silkspanner is the fourth dragon with more than two pairs of legs, with the others being the Fireworm, the Hackatoo, and the Thunderpede.
 * The Silkspanner is the third dragon to originate from a comic and the second to be later introduced in Dragons: Rise of Berk.