Shaggydog

Shaggydog is one of six direwolf cubs found by the children of House Stark. Shaggydog is adopted and raised by Rickon Stark, the youngest of the five Stark children.

Season 1
Shaggydog leaps out at Bran and Osha in the Stark family crypt, frightening them and causing them to fall over. It is said that Shaggydog should be tied up, but he didn't like it.

Season 2
After Theon has taken Winterfell, Shaggydog is seen fleeing through the Godswood with Osha, Bran, Rickon, Hodor and Summer.

In the books
In the Song of Ice and Fire novels Shaggydog is the fiercest and least-disciplined of the five wolves, reflecting Rickon's willful nature. Bran thinks the wolf's name is stupid (though of course he was named by a small child), and "Shaggy" soon becomes a preferred name. He is described as black, with bright green eyes