"He doesn't like chains."
Rickon regarding Shaggydog.

Shaggydog is a direwolf bonded to Rickon Stark. Born with five other siblings, Shaggydog has black fur with bright green eyes. Shaggydog remained Rickon's constant companion, and later followed Rickon when he left Winterfell. Shaggydog later went off with Rickon and Osha when they departed from Bran, Jojen, Meera, Hodor and Summer, going off towards Skagos to keep Rickon safe. According to reports, he remains there with Rickon. In the show however, Rickon and Osha were captured by House Umber and presented before Ramsay Bolton, with Shaggydog killed and its head decapitated as proof that Rickon was legitimate, and not an impostor.