One of the Namas of Shiva is Krittivasa ("who has skin as his garment"), a name that refers to His slaying of Gajasura and wearing his hide/skin on his body. Another Nama is Gajaha, the slayer of the elephant.
According to the Shiva Puranas Gajasura is the son of the Mahishasura, the buffalo demon who was killed by Goddess Durga. To avenge his father's death, he is said to have performed a penance. Lord Brahma was impressed and granted him a boon that he would be killed only by a Jitendriya, one who has overcome all lust and desires. Thinking that he was invincible, the demon harassed the people of the Earth, asking them to worship him instead of the Gods. He went to Benares and attacked the sages who prayed to Lord Shiva for help.
Shiva emerged from this linga, slew the demon, skinned the animal and wore its hide around his body.