宋高僧傳 2.18

2.18

又邙山有巨蛇，畏見之，歎曰：「欲決瀦洛陽城耶？」以天竺語呪數百聲，不日蛇死。乃安祿山陷洛陽之兆也。

Furthermore, on Mount Mang there was a giant serpent. When Śubhakarasiṃha saw it, he sighed and said: "Do you wish to breach the dikes and inundate the city of Luoyang?" He uttered several hundred chants in the Indian tongue, and within a few days, the serpent died. This was an omen of An Lushan's capture of Luoyang.