The episode title is Spanish for "The Fierce Bull". This is the common Spanish name of the fighting bull breed.
Father Consolmango tells Jack only 1 Peter 5:5, from which the team deducts that the unsub must have been born on May 5th. It is very convenient that 5-5 was used, as the American interpretation is month-day, while the European interpretation is day-month. In this case they both lead to the same date.