When Emperor Wu of Han (156-87 BCE, r. 141-87 BCE) travelled east, he arrived at the Hangu Pass, where he found a thing in the road, its body several zhang in length (a zhang is c. 3.33m), and like an elephant ox in shape, with dark eyes and a sparking energy, its four feet buried in the earth, moving around but not travelling. The various officials were very alarmed, but Dongfang Shuo requested wine to pour upon it. He poured out several dozen hu, and it disappeared. The emperor asked why, and he replied: “This is called a you (i.e., a ‘sorrow’); it is born of suffering. This must have been the site of a Qin prison, or, if not that, a site where prisoners were gathered and moved. As wine removes sorrows, we were able to make it disappear.” The emperor said: “Only an expert in the natural world could deal with this.”
Li Fang 李昉, et al., Taiping guangji 太平廣記 (Extensive Gleanings from the Era of Great Harmony), 10 vols (Beijing: Zhonghua shuju, 1961), viii, 359.2839-40:
 This is Dongfang Shuo 東方朔 (c.160-c.93 BCE, courtesy name Manqian 曼倩), a famous writer and Daoist of the Former Han court. On him see http://www.chinaknowledge.de/History/Han/personsdongfangshuo.html; Hanshu 65.2841-74.