Staff Sergeant Reckless (1948-1968) is a decorated war horse that served with Fifth Marine Regiment during the Korean War. The Mongolian breed mare was purchased in October 1952 at a racetrack in Seoul, Korea and then trained to be a pack horse for the Recoilless Rifle Platoon, Anti-Tank Company, Fifth Marine Regiment. During the war she transported supplies, ammunition, and evacuated casualties; often without the need for a handler after quickly learning each route. She especially distinguished herself during the Battle for Outpost Vegas in March 1953, following which she was promoted to corporal. In 1954, she was promoted to sergeant following the conclusion of the war and in 1959 promoted to the rank of staff sergeant.

She is recognized by a plaque at the Camp Pendleton stables, a statue dedicated at the National Museum of the Marine Corps in 2013, a statue installed at Camp Pendleton in 2016, and a statue placed at the Kentucky Horse Park in 2018.

Her decorations include the Purple Heart (with 1 gold star), Presidential Unit Citation (with 1 bronze star), Navy Unit Commendation, Marine Corps Good Conduct Medal, National Defense Service Medal, Korean Service Medal (with 3 bronze stars), Dickin Medal (awarded posthumously), Republic of Korea Presidential Unit Citation, and the United Nations Korea Medal.