Soma is the god of ecstasy. His nectar, amrita was food for the gods. He is the son of Varuna. Varuna is the god of the oceans from which the moon rises.
Soma became equated with the god Chandra, who originally was the moon deity.
The moon was considered the cup which held the drink Soma for the gods, and one reason that the moon waxed and waned was due to this fact. When the moon waned, it was because the gods were drinking down all the Soma; as it waxed, the god was re-creating himself, only to be consumed again once the cup was again full.
The cup was filled again by the oceans.

Soma (drink):
As a drink, Soma is the ambrosia of the gods and Agni is the great drinker of the substance. Soma is now everything what is offered up to the ritual fire.
It was also a drink for mortals, a golden-hued nectar which was derived from the Soma plant, which may be a species known as ephedra vulgaris or the Amanita muscaris. This drink brought hallucinations and ecstasy to those who consumed it.
He is depicted as a copper coloured man with 2 arms.
He sits or stands in his battle chariot with red banner. His chariot is pulled by an antelope or 10 horses.

Attributes:

Mace (Gada) :
A staff with a tapering end used as a weapon in close combat.
It symbolizes the power over the nature’s laws. Also a symbol of Vishnu.
A club made of human bone with a skull on the end of it is carried by Devi, Durga, Kali and Bhairab.

Protecting gesture of the hand:
Protection

Riding Animal :

Antelope.
The antelope symbolizes nature and king of the animals.

Other names of Soma :
Chandra.