Deer
The deer is a psychopomp, a guide to transformation, a bridge to the unconscious, to new knowledge and discoveries; in other words, for the soul. Depending on the dreamer's attitude, the deer can be a symbol of light and rejuvenation, but it can also be a negative symbol – it can lead the dreamer astray or appear threatening. The deer roars and becomes aggressive during mating, and is a distinctly masculine symbol.
Renewal
The deer sheds its tree-like antlers after mating, only to let them grow back again. There is a legend that tells how the deer swallows a snake, spits out the poison, sheds its antlers, and lets new ones grow. The snake is, of course, a symbol of rebirth. The deer is said to shed its antlers by streams, and according to other legends, it can also make springs rise from the ground.
Wholeness
The deer is sometimes depicted with a circle and a cross between its antlers, as a symbol of rebirth and wholeness. Since it can renew itself, it is an allegorical image of Christ. Mercurius is also depicted as a deer and is sometimes called "the fleeing deer" (cervus fugitivus) because it is elusive and hard to catch, like quicksilver; with its characteristic dual meaning, the fleeing deer was simultaneously the philosopher's stone, lapis.
Death and Ghosts
The image of the deer that transforms and is reborn also contains death as a symbol. For example, the deer was believed to be able to lead to death, and it was associated with ghosts and rebirth rituals.
Psychopomp
The Celtic god Cernunnos had antlers on his head and ruled over vegetation and death, but also over communication with other worlds and was said to guide the dead to the afterlife. Although these attributes are largely speculative, as little is known about this god, they follow the archetypal image of the deer as a psychopomp.
Love and Sexuality
According to Germanic legends, the deer is associated with love and has a strong erotic quality. In some Germanic plays and ceremonies, participants dressed as stags and hinds, and then acted out sexually charged behaviors.
The Self
All of the above suggests that the deer "is a bearer of the archetype of the Self and the principle of individuation." (The Grail Legend, p. 260.)