Morrígan, in one of her earliest narative accounts, appears as a singular entity in the Ulster Cycle of Celtic mythology; a proponent of the Táin Bó Cúailnge.
She first visits Cu Chulainn in the form of a young woman offering her love and aid in combat, though he summarily rejects her. Enraged at this slight, the goddess then visits him the next day during battle in the form of an eel who stifles his progress at the ford. The following day she arrives as a wolf driving cattle across the ford, and the next day, as a furious heifer at the front of a stampede. Cu Chulainn, however, is unabated in his efforts, delivering a blow to each animal form before resuming combat.
She later appears before Cu Chulainn as an old maid with three wounds resembling those received in her animal forms. She offers him three drinks of milk, and receives his blessings three times, each healing a corresponding wound.