Achala is a wrathful deity from the pantheon of Tibetan Buddhist gods.  His wrathful appearance is to scare away evil spirits and to protect the devotee.  Achala’s chief role is to awaken the initiate to his or her own negative aspects and to transform these into compassion and wisdom.  Also, he may be invoked to eliminate both inner and outer hindrances.  This image was taken from a 13th century Tibetan painting (thanka).