Bull, played by Bobby "Slim" Jones, is a character from the film Aliens vs. Predator: Requiem.
Bull was aboard the scout ship that carried Scar, the fallen hunter after the events of Alien vs. Predator. Nobody aboard knew Scar was gestating a Predalien.
Bull overheard a fellow Yautja in distress and he rushed to investigate. He saw the Predalien attacking his comrade. Bull took a shot but missed and punctured the hull, causing the ship to crash land in Gunnison, Colorado.
Bull survived the initial crash. He had enough time to send out a distress signal before the Predalien headbit him and killed him.