Wow. Fantastic !
This guy has some impressive ones too.
https://youtu.be/HMq30DuxMLA
Any idea what type of clay they use? I might give it a try. 😊
If you want it to harden off then perhaps try Milliput, which is a two-part epoxy putty.
https://www.milliput.com/index.html
My 84 year old father has used it for years to model military figures in 54mm.
Monster clay
Seriously impressive stuff