The Chicken From Outer Space - Pilot (1995)

An alien chicken arrives on the farm, hoping to invade. Courage witnesses his arrival and alerts Muriel and Eustace, though they don't believe him. Courage follows the chicken to find him strangling the chickens in the farm's chicken coop to death. He calls his owners once more, and this time they follow him. Back at the coop, all the chickens have mysteriously vanished, except the alien chicken, which is posing as a normal chicken. Muriel takes a few eggs from it, and begins to cook them for breakfast. Courage fights with the Chicken in several different contests, while Muriel feeds Eustace some of the Chicken's eggs, which transform Eustace into a monstrous Chicken. After many competitions and fights, Courage manages to defeat the Chicken by frying it with its own laser gun. The Chicken-Eustace is defeated in the same way. However, a mouse starts to eat the Chicken-Eustace's ashes. Courage ends by saying "This shouldn't happen to a dog!"

P.S.The characters were drawn differently than they were in the series itself.