Markiplier's Iron Lung Broke A Horror Movie Record That Has Nothing To Do With The Box Office

Mark "Markiplier" Fischbach's horror film "Iron Lung," based on the video game by David Szymanski, is one of the biggest success stories of 2026. Made for a mere $3 million and directed by a famed YouTuber taking a crack at feature filmmaking for the first time, "Iron Lung" has earned $51.2 million to date. Its success — paired with the successes of other YouTube-to-theaters hits like "Skinamarink," "Obsession," "Backrooms," and "The Amazing Digital Circus: The Last Act" — has proven that 2010s Hollywood is dead, that 50-year-old fantasy I.P. will be providing fewer and fewer hits, and that a new generation of filmmakers is nigh. So far, these films have been made mostly by white dudes ("Digital Circus" notwithstanding; director Gooseworx is a trans woman), but the door is open for more diversity. 

The premise of "Iron Lung" is downright Lovecraftian. The movie is set entirely aboard a one-man submarine as it descends to the ocean floor on a distant planet. The sub is piloted by a half-mad convict named Simon who can only see what's in the oceans around him via quickly snapped X-ray photos. X-rays are needed because the ocean is entirely full of blood (!). When the sub rests on the ocean floor, it shifts about, as the ground beneath it is constantly clotting (!!). There are mysterious, toothy leviathans lurking within the blood. Oh yes, and the sub is rusty and old, and blood leaks in throughout the movie, filling the hold. 

As one might guess, "Iron Lung" made use of a heck of a lot of stage blood to fill its set. Indeed, according to a Deadline interview with Markiplier, "Iron Lung" broke the cinematic record for volume of blood used on camera, employing nearly 80,000 gallons of the stuff.

Markiplier went into great detail about the blood he used for "Iron Lung." He noted that it was shipped in semi-trucks and had to be diluted before it could be used; it was very viscous at first. Rather than calculate the blood volume based on the amount ordered, Markiplier decided to calculate the set volume and the pressure at which the blood was pumped into it. He explained his process thus: 

"We had two pumps, I believe they were Honda WH20s. They pump at 119 gallons per minute. But I'm not going to 100% of the flow rate because other factors can affect that. So, I figured 80%, and 80% of two of those pumps is 190 gallons per minute. I have [behind-the-scenes footage] of each basin getting filled. I technically know the volumes, but they were filled multiple times, filled and drained, filled and drained, and so I can calculate based on the time it took to fill each one, and how many times." 

Markiplier said that he shot the blood-flooding scenes near the end of filming, over the course of a week. During that time, he ran the blood pumps for eight hours in total, but decided to be conservative in his calculations and said he'd calculate it as seven hours. He finished by saying:

"So, you do seven hours, which is 420 minutes, times 190 gallons per minute, which is 80% of the two flow rates, that's 79,800 gallons of blood."

For context, an Olympic-sized swimming pool is about 660,000 gallons. If Markiplier's estimate is accurate, then "Iron Lung" likely used more blood than any other movie in history. Of course, this is fitting for a movie about an ocean of blood. 

The 79,800-gallon estimate noses out the previous estimated record holder, Fede Álvarez's 2013 film "Evil Dead," which featured a climactic scene of someone being chainsawed in the face while blood rained from the sky. According to the film's IMDb trivia page, the film used 70,000 gallons of blood, with a full 50,000 being used on the blood-rain sequence alone. The original 1981 Sam Raimi film "The Evil Dead," meanwhile, only used about 200 to 300 gallons. 

Here at /Film, we also talked to filmmaker Lee Cronin about the volume of blood he employed for "Evil Dead Rise," and he said that he still drummed up about 1,700 gallons. Not anywhere near the record. According to an article for Far Out Magazine, the 2019 movie "It: Chapter Two" is another famous bloodbath, filling an entire bathroom with blood to drown the character of Beverly (Jessica Chastain). That film used only 5,000 gallons of blood, but handily outstripped the famous scene in "The Shining" in which an elevator door opened to reveal the elevator full to the brim with blood. That scene, it seems, only used 300 gallons. 

Having seen "Iron Lung," I have no trouble believing Markiplier's estimations of its record-holding use of blood. There is no evidence to go on other than the filmmaker's own review of the footage and estimates based on the rate of liquid flow, but the film's main character spends the entire final portion of the movie standing in a large pool of the gooey stuff, so it's believable that he is accurate. If he and Fede Álvarez wanted to debate the matter, it's something that the two filmmakers will have to arrange themselves.