"I thought my eyes were deceiving me," Lasca said. When she saw the flicker of the snake's tongue, she knew it was a snake.

She screamed and ran from the bathroom, slamming the door and calling the county Department of Animal Services.

The snake, identified as a Colombian rainbow boa, was curled up behind the toilet when an animal services employee arrived at the office in a building at 5th and G in downtown San Diego, which was once city hall.