SCP-1156 is a male domesticated horse (Equus ferus caballus) of indeterminate breed and unknown age, approximately 1.7 meters in height. SCP-1156's tongue, palate, lips, and vocal cords are shaped in a manner not found in non-anomalous horses, allowing it to produce phonemes used in human speech. SCP-1156's brain is approximately ██% larger than the brain of a non-anomalous horse, and possesses several anatomical regions of unknown purpose or function.

SCP-1156 is sapient and is able to speak English with a thick accent resembling that historically spoken by natives of the East End of London, UK ("Cockneys" in common use), and claims to have been born and resided in the London borough of Whitechapel prior to its coming into Foundation custody. SCP-1156 identifies itself as "Wellington G. Wonderhorse" and describes itself as part of a community of sapient horses living openly throughout the East End (a claim which has not yet been corroborated by Foundation research.) SCP-1156 has demonstrated a limited ability to manipulate tools and simple machines with its lips, teeth, and tongue, including an ability to write by holding a pen in its mouth.

SCP-1156 possesses a limited form of telekinesis, comprising an ability to dress itself by spontaneously manifesting clothing tailored to fit a large horse directly onto itself. Most frequently, this clothing takes the form of a silk top hat and a light blue scarf bearing the monogram "W.G.W." in gold embroidery, though SCP-1156 has demonstrated an ability to produce other articles of clothing, including neckties of various styles, coats, eyeglasses, masks, heraldic banners, harnesses, bridles and bits, and on one occasion upon a request from research staff, a full suit of articulated plate armor. Clothing manifested by SCP-1156 spontaneously disappears when SCP-1156 dresses itself differently; the source of the clothing and its ultimate disposition upon demanifesting is unknown. Forensic examination of the clothes themselves indicates that they are composed of common fabrics and metals and bear no anomalous properties in and of themselves.

SCP-1156 was acquired by the Foundation in 20██ following a raid on a country club in [REDACTED], UK, owned by Marshall, Carter & Dark Ltd. SCP-1156 claimed to have been taken prisoner by MC&D six months prior after responding to a want ad for coach horses and forced to perform various tasks for the guests of the club. SCP-1156 describes itself as a professional coach horse and has been convinced at this time that the Foundation is employing him for that purpose.