The Ouroboros (n.) says what all alchemy says: redeemer and redeemed, sacrificer and sacrificed are one, as when Christ in the Eucharist drinks his own blood.
The Ouroboros (n.) is the dragon that devours, fertilizes, begets, kills and revives itself — made of opposites and their uniting symbol at once: poison, basilisk, panacea, saviour.
The Ouroboros (n.) is the self-devouring serpent, the arcane substance that suffers no hunger because it eats itself and slays itself with its own dart like the scorpion, yet revives itself with its own good poison.
The Ouroboros (n.) is the ancient pagan image of a being that begets and devours itself, paralleled in Chrysostom's remark that Christ first ate his own flesh and in Tertullian's Alpha and Omega.
The Ouroboros (n.) is the symbol par excellence of the union of opposites, the alchemists' version of "extremes meet," and so stands for the goal of the work rather than its chaotic beginning.