Ack

Ack is one of the Scuttleclaw juveniles that first appears in the movie, How to Train Your Dragon 2, and then is named in the graphic novel, The Serpent's Heir.

Carrying Riders
In the movie, How to Train Your Dragon 2, the Dragon Riders and company are stranded at Valka's Mountain, while Drago Bludvist moves toward Berk to attack the village. The only dragons immune to the control of a Bewilderbeast is baby dragons, and there is a group of young Scuttleclaws available. The Riders mount and fly the unruly juveniles, but eventually make it back to Berk to save the day.

As Gobber's Charges
In the aftermath of the attack by Drago, the Scuttleclaw juveniles take up residence on Berk. Hiccup, now Chief, leaves Gobber in charge while he leaves to help the people of Nepenthe. The brood of Scuttleclaws wreak havoc to Gobber's shop, chewing on everything and not listening. However, Bonesnarl the Thunderclaw arrives, and takes charge of the wild dragon children and gets them in line.

Physical Appearance
It is not specified which of the several Scuttleclaw juveniles Ack is. The juveniles are a variety of colors including predominantly: blue, purple, yellow, green, and red.