Finished the mask in 2 days only, starting on Friday night.
Spent 3 hours on building it and almost a whole day I needed for the paint job.
I cut out a thick piece of foam and covered it with a thermoplastic of your choice.
Shaped the eyes to let them pop out a bit more to give the mask more depth.
The spikes are 10 identical pieces which I cut out of foam and covered with thermoplastic. Then stuck it to the mask base.
The paintjob was done with a few layers of primer and then I used acrylics mostly to make all the details.