I've heard that Wukong has a heart of gold (literally), as well as iron lungs, and a metal spine from being in Lao Tzu's furnace and eating molten Copper from Guan Yin and was wondering if this is true.
Monkey states that in ch. 34:
When old Monkey caused great disturbance in the Celestial Palace five hundred years ago and was refined for forty-nine days in the eight trigram brazier of Laozi, the process in fact gave me a heart strong as gold and viscera hardy as silver, a bronze head and an iron back, fiery eyes and diamond pupils (Wu & Yu, 2012, vol. 2, p. 131).
The legend of his adamantine body predates the 1592 JTTW. For instance, Sun claims the following in the early-Ming zaju play:
I plundered Laoziās gold Pill of Immortality, and have endured so many alchemical transformations that my muscles are brass, my bones iron, my eyes fire, my pupils gold, my asshole lead andĀ my prick is pewter (Ning, 1986, p. 142).Ā
Another example comes from the 13th-century JTTW. He is referred to as the the āBronze-Headed, Iron-Browed King of the Eighty-Four Thousand Monkeys of the Purple Cloud Grotto on the Mountain of Flowers and Fruitsā (Wivell, 1994, p. 1182). And the story ends with the Tang Emperor Taizong enfeoffing him as theĀ āGreat Sage Steel Muscles and Iron Bonesā (Wivell, 1994, p. 1207).
Ning, C. Y. (1986).Ā Comic Elements in the Xiyouji ZajuĀ (UMI No. 8612591) [Doctoral Dissertation, University of Michigan]. ProQuest Dissertations and Theses Global.
Wivell, C.S. (1994).Ā The Story of How the Monk Tripitaka of the Great Country of Tāang Brought Back the SÅ«tras. In V. Mair (Ed.),Ā The Columbia Anthology of Traditional Chinese LiteratureĀ (pp. 1181-1207). New York: Columbia University Press.
Wu, C., & Yu, A. C. (2012).Ā The Journey to the WestĀ (Vols. 1-4) (Rev. ed.). Chicago, Illinois: University of Chicago Press.