Cretan Bull

In the principal mythic strand recorded in classical summaries, Poseidon sent Minos a snow-white bull as a divine sign that Minos should sacrifice it to the god; Minos instead kept the animal and substituted another for the sacrifice. Enraged, Poseidon caused Pasiphaë to fall in love with the bull, resulting in the birth of the Minotaur. The bull therefore originates as a god-sent animal whose retention by Minos sets in motion a chain of divine retribution and monstrous birth (Wikipedia "Background"). Scholarship cited in the sources also links the bull motif to Minoan cultic imagery, while noting that some narrative elements (notably the Pasiphaë episode) appear in literature relatively late and may reflect later reinterpretations of Bronze Age material (Wikipedia "Origin").

The cited sources give only limited physical description: the bull sent by Poseidon is explicitly described as a 'snow-white' specimen in the accounts summarized (Wikipedia "Background"). Other retellings and summaries refer to it simply as 'the bull' without further anatomical detail; no systematic descriptions of size, horn shape, or other markings are provided in the cited materials.

The Cretan Bull's agency in the sources is primarily physical and divinely caused rather than described as an occult spirit: Poseidon's sending of the bull and subsequent divine anger provide the causation for its role. In mythic episodes the bull wreaks material damage — uprooting crops, leveling orchard walls, trampling or killing persons (accounts differ on precise victims) — and becomes the object of Pasiphaë's divinely induced passion that produces the Minotaur. Its destructive behavior prompts heroic intervention: Heracles captures it as one of his labours and ships it to Eurystheus in Tiryns, and in variant accounts it later breaks loose and wanders to Marathon where it continues to devastate the countryside until Theseus or other heroes capture and/or sacrifice it (Wikipedia "The seventh labour of Heracles"; Archive LP0010 summary).