A new video shared online showcases how Naughty Dog created one of the most nightmarish video game moments of 2020 in The Last of Us Part 2. The video highlights the way the studio was able to animate a late-game boss battle for the sales record smashing game with a disturbing degree of realism.

In the later half of The Last of Us Part 2, the player is tasked with playing as the controversial character Abby as she ventures deep into the ER floor of a heavily infected hospital controlled by the WLF, of which she is a member. The WLF are suspicious of Abby for going AWOL previously and try to capture her and bring her back to the WLF’s leader, Isaac, for questioning. Abby’s friend in the WLF, Nora, releases Abby from custody though, and sends her on her own to the ER floor that has not seen a non-infected human in over 25 years.

RELATED: How Abby Brings the Story of The Last of Us 2 Full Circle

While on this previously untouched floor, Abby encounters several humans infected with the cordyceps fungus that have grown together into a massive fungal monstrosity while trapped for on the ER floor. Players who have had the displeasure of encountering this creature were likely equal amounts disgusted and terrified by the monster’s grotesque details. At one point during the boss battle, Abby manages to hurt the beast enough that one of the attached infected peels itself from the flesh of the monster to flee. This particular moment is rather gruesome and upsettingly realistic for a zombie fantasy scenario, and now fans can know why.

Lead animator at Naughty Dog, Jeremy Yates, tweeted out a behind the scenes video of the motion capture session where the aforementioned scene was recorded. The beast and human-sized infected that peeled itself off were in-fact two different mo-cap actors that were being held together by others on set.

One person held the actress playing the smaller infected, Amy Johnston, against the actor playing the main beast, Chris Robbins, by using an elastic belt, while another held her by the arm, and a third person held her leg. Each person released another part of her at a separate time to simulate the smaller infected breaking free.

That is where the beast received its frighteningly lifelike animation but lead animator Jeremy Yates was sure to credit David Kim for the tearing flesh detail, and the artist who designed the monster (appropriately named the Rat King), Danilo Athayde.

This isn’t the only behind the scenes look fans of The Last of Us Part 2 have been given. Recently, the director of the game, Neil Druckman, revealed a scene that was cut towards the end of the game involving Ellie. The scene in question would have dealt with Ellie suffering more PTSD relating to Joel’s death.

Fans of the Last of Us have plenty to look forward to than just more peaks behind the curtains. Not only is a TV series based on the game headed to HBO, but there is also a forthcoming standalone multiplayer mode set in the world of The Last of Us as well.

The Last of Us Part 2 is available exclusively for PlayStation 4.

MORE: What to Expect From The Last of Us 2's Standalone Multiplayer