"They trap you in a web and cover you in slime before they eat you."
―Hiccup to Fishlegs.

Traits and Abilities

Stickyworms have many, many legs, and three long tongues. Their saliva is black and is used to make the Stickyworm webs with which to trap prey. They are described as being double the size of a boa constrictor, as well as digesting prey similar to snakes, i.e. you may see large bulges along their bodies of digesting prey.

Stickyworms are particularly sensitive to salt. This can be used to fend them off.

Stickyworms also have large eyes to catch any light in the caves that they live in. Their eyes are also capable of super eyesight and X-ray vision.

How to Train Your Dragon (series)

How to Steal a Dragon's Sword

Stickyworms are mentioned when Fishlegs asked Hiccup what dragons they were likely to meet in the dungeons at Flashburn's School of Swordfighting. In fact, they found Flashburn hanging upside down in the web of a Stickyworm.