Alarms were raised at Ueno Zoo after two keepers in a zebra costume broke free from the animal's pen, and 'injured' two staff and a visitor.
Some 150 zoo workers, policemen and ambulance crew played their part, wearing hard hats and wielding sticks and nets in an attempt to capture the escapee.
The fake zebra finally fell to a fake tranquilizer gun.
But to many visitors, the spectacle looked funny rather than serious."His tail looked so funny," said 4-year-old Futaba Amagasaki, who was visiting the zoo with her grandfather.
Every year the drill features different escaped animals, such as gorillas, lions and even rhinoceros.
Zookeepers in Japan have only had to deal with three escapees in the last 40 years.