The strange metallic dragons created by Melkor with his smiths and sorcerers for the attack on Gondolin are placed into context as medieval automata.
"Medieval Automata and J.R.R. Tolkien’s The Fall of Gondolin,"
Journal of Tolkien Research: Vol. 16:
1, Article 6.
Available at: https://scholar.valpo.edu/journaloftolkienresearch/vol16/iss1/6