- "They trap you in a web and cover you in slime before they eat you."
- ―Hiccup to Fishlegs.
Stickyworms have many, many legs, and three long tongues. 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 appear to have short thin wings.
Stickyworm saliva is black and is used to make the Stickyworm webs with which to trap prey.
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.
Stickyworms are particularly sensitive to salt. This can be used to fend them off.
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.
Stickworms are detailed in this reference book, as well as appear in the 'Dragon Key' at the back of the book.