Symbolism of Mahakala in the 6-armed Manifestation:
The Protector’s body is midnight blue, symbolic of the changeless Dharmakaya.
His three eyes symbolize his knowledge of the past, present and future, and also the manifestation of the three bodies of Buddha.
The crown adorned with five skulls symbolizes the transformation of the five poisons of anger, desire, ignorance, jealousy and pride into the five wisdoms.
His six arms symbolize the attainment of the six Perfections: generosity, patience, morality, diligence, meditation and wisdom. The kartika or triku [or trigu, pron. tigu] the ritual curved knife, cuts attachment to ego.
The kapila or skull bowl filled with blood symbolizes the subjugation of the maras or evil ones. (An alternate interpretation can be found in other contexts.)
The rosary symbolizes his continuous activity for the benefit of beings.
The damaru or hand-drum symbolizes his power over the dakinis. (Also, different interpretations in other contexts.)
His trident symbolizes his power over the three kayas — the spheres of desire, form and formlessness. (An alternate interpretation can also be found.)
The lasso binds those who break their vows.
His two feet are the means and the wisdom to accomplish his task. That his left leg is straight and his right leg bent symbolize his accomplishment of the benefit to oneself and to others. He tramples on a vinayaka, to symbolize his destruction and dispersal of great obstacles.
The sun on which he stands symbolizes his illumination of the darkness of ignorance.
His lotus seat symbolizes purity undefiled by samsara.
The surrounding blazing fire symbolizes his activity that consumes neurotic states.
The tiger skin stands for purification of desire; the elephant skin for purification of pride, and the snake, for the purification of anger.
His other ornaments together symbolize that he has all the qualities of a Buddha.
The material about the symbolism of 6-armed Mahakala derives from a Gelugpa sadhana (ritual) of Tara that includes an offering to Mahakala. The whole was produced in Jan. 1994 by Dharma Therapy Trust under Ven. Geshé Damchö Yönten and is available unedited at Lamrim.org.uk