Stonesnake

"Stonesnake" is a minor character in the second season. He is played by an unidentified extra. Stonesnake is a member of the Night's Watch, a Ranger serving under Qhorin Halfhand.

Season 2
After meeting the force led by Lord Commander Jeor Mormont at the Fist of the First Men, Qhorin Halfhand selects Stonesnake, Ebben and Dalbridge for a scouting party to ambush a group of wildlings.

In the books
In the Song of Ice and Fire novels Stonesnake is also a Ranger serving under Qhorin Halfhand. He's dubbed Stonesnake for his ability for climbing mountains and cliffs.