A smoke bomb (煙玉, kemuridama) creates a cloud of smoke when it detonates. It may look like small spheres wrapped in paper or canisters. Smoke bombs are typically used to blind opponents and make them easier to attack. Alternatively, ninja can use smoke bombs on themselves so that opponents cannot see what they are doing. They can also contain poison or sleeping gas, the latter of which was used by Sakura Haruno, who learned to make the substance from Tsunade herself.