It took about 4 hours to transform stuntmen into stone men for Sunday's 'Game of Thrones'

HBOTyrion and Jorah go down a troubled path Sunday evening.

If you aren't caught up on "Game of Thrones," there are some spoilers ahead.

Near the end of Sunday's "Game of Thrones" we finally met the long-hinted at stone men, men afflicted with greyscale. The highly contagious and deadly disease nearly claimed Stannis Baratheon's daughter Shireen as a newborn.

Anyone who comes down with greyscale is usually exiled to a faraway city in ruin as their skin slowly turns stone-like. That's not only because of the disease's ability to spread like wildfire, but also because it can affect the brain and turn the recipient mad. 

In Sunday's episode, Tyrion (Peter Dinklage) and Jorah (Iain Glen) get ambushed by a flock of stone men while sailing through Valyria. 

We don't get a really good look at the scaley, hardened creatures, but a feature released by HBO Sunday evening shows exactly how the stuntmen prepped to get into character.

We saw the stone men like this Sunday night:

HBOVery tough to see, right?

Here's how they look in the light.

HBO

HBO

They blend in with the rocks in the background.

HBO

It takes an enormous amount of work to get them to look that way.

Prosthtics supervisor Barry Gower says it was about a four-hour process to transform just the head and neck of various stuntmen into the stone men of Valyria.

Here, one of the stunt men sit down in the makeup chair. Take note of the changing clock in the background. It's about 3:45 (it looks like a.m. from the changing light in the video).

HBO

4:45: Hair is covered up and the chest and neck are painted.

HBO

A little after 5:05: A prosthetic is being placed onto the face.

HBO

Around 6:36: Small details are being painted onto the face. Gower explains that different textures including elephant skin and cracked river beds served as inspiration for the stone people's look.

HBO

It's nearly 8, just a little over four hours later, and the stunt man is finally looking like a stone man.

HBO

Here's how the transformation looks from beginning to end:

HBO

Outside the trailer, even more details are put in place with the thinnest of brushes.

HBOHBOStuntman Calvin Heasman compares the process to wearing a wetsuit, but on your face. 

HBO"Game of Thrones" stone man stunt man Calvin Heasman describes what it's like to be one of the stone men on set.

HBO

"Quite uncomfortable, not gonna lie," Heasman explained.

You can watch the full feature showing the making of the stone men scene via HBO below: