MASSIVE SPOILER ALERT! The burning question left in the wake of the latest episode of "Game of Thrones" is not whether the Night's Watch will survive the Wildlings' attack, but whether it's possible for a human to crush an adversary's cranium with his or her bare hands.
Saying anything more about the grisly ending of the "Mountain vs. Red Viper" trial by combat, which sealed the fate of a major character (or did it?!), would go way over the spoiler line.
Let's just say that this biomechanical conundrum has come up several times before in a cinematic context. The same question was raised when Benedict Cumberbatch's Khan character dispatched a foe in "Star Trek Into Darkness," or when Rutger Hauer's replicant character offed his creator in "Blade Runner."
The most detailed research into this specific question was done by Kyle Hill for Slate when the Star Trek movie came out, and updated this week for Nerdist. His bottom line, primarily based on a bike-helmet study published in the Journal of Neurosurgery: Pediatrics, is that a skull crush would require 520 pounds (2,300 newtons) of force. That's thought to be roughly twice as much force as human hands can typically muster.
Two things to keep in mind here: First, the characters in "Game of Thrones" are, um, fictional. Second, there's more than one way to crack a skull. Some reports suggest it could take as little as 16 pounds (73 newtons) of force to cause a simple fracture. A Japanese study put the figure for a full-on crushing as high as 1,200 pounds (5,400 newtons). Conclusion: Your Mountain may vary.
Since bare-handed skull-crushings apparently are done only by super-strong fictional characters, we can safely assume it's beyond the capability of mere mortals. However, one of the grisliest elements of the "Game of Thrones" scene — the eye-gouging part — is apparently doable, and potentially lethal. DO NOT TRY THIS AT HOME!