The Marvel Cinematic Universe's Tony Stark used his brilliance and insatiable work ethic to build at least 42 different Iron Man armors during his time on the job. Many of these suits are simply more advanced variations of his iconic base Mark III model, while others act as transitionary prototypes for testing new technologies. However, there were also a number of highly unique and specialized designs that helped Tony be prepared for any type of conflict, rescue operation, opponent, etc. Though by no means an exhaustive list of all of these armors, here are some of the most interesting examples.

Mark I

Iron Man Mark I Flamethrower Weapon MCU

Though it's tempting to classify the Mark I as a prototype, the truth is that it was designed for practical use from the beginning and was even used in active combat. The only suit to be built on a practically non-existent budget and without anything more than crude technology, it nevertheless contained a number of impressive features. In addition to being bulletproof, the design also housed a crude rocket-launcher, rocket boots and the only flamethrower ever seen on an Iron Man armor. While the suit was successful in its mission, Tony never really went back to the same lumbering design for his commonly worn suits (the Hulkbuster being a situation-specific model), preferring a more sleek and refined look.

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Mark XVIII "Casanova"

The so-called "Casanova" suit was the culmination of several earlier models, all experimenting with cloaking technology. In addition to featuring the Mark XVI's advanced stealth technology, the Casanova improved on the earlier design by also being viable in combat, possessing an oversized reactor similar in strength to that of the Mark XVII. Though the suit may have been interesting to see used by Tony, it, unfortunately, met its end at the Battle on the Norco. At the same time, it is at least possible that Tony incorporated the Cassanova's technology into his more mainstream suits -- he was somehow able to evade Thunderbolt Ross' radar while heading to Siberia in Captain America: Civil War.

Mark XXVI "Gamma"

Much like the Cassanova was the finished version of the stealth suit, the "Gamma" suit seems to have been the perfected construction-oriented armor. Featuring two prominent arm-mounted jackhammers that could be used both for hard labor and combat, this model is certainly one of the bulkier and stronger armors in Tony's armory. In addition to its raw strength, the suit also protected against gamma radiation (hence the name) and hot and cold temperatures, as well as electrical currents. Some of Tony's later designs may have incorporated ideas first explored in the Gamma, including the Mark L's arm hammer and the heating system in Spider-Man's Stark suit.

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Mark XXXV "Red Snapper"

red snapper

The aptly-named "Red Snapper" was created primarily to save lives rather than to win fights. What the suit lost in weaker repulsor technology and load-out it gained in its unique retractable arm-mounted claws -- presumably for lifting people to safety -- and its ability to resist natural disasters, such as floods, hurricanes, earthquakes and fires. The suit was also destroyed, along with many others, in Tony's confrontation with Aldrich Killian and his Extremis soldiers. There's no easy parallel to show what this model may have helped Tony design later down the line, but it could be that a suit intended to survive natural disasters is very similar to a suit intended to survive the Hulk.

Mark XXXVII "Hammerhead"

Yet another suit belonging to the Iron Legion, the Mark XXXVII was code-named "Hammerhead," and is surprisingly the only Iron Man armor designed for underwater operations. As with any standard diving suit, the Hammerhead has its own external supply of oxygen and is watertight to prevent flooding. But of course, it wouldn't be a Stark suit without some extra features, such as turbines for navigation, lights and even submarine-like torpedoes. The Hammerhead met its untimely end when it was destroyed by Tony as part of his brief retirement from his superhero role at the end of Iron Man 3.

Mark XXXIX "Starboost"

Continuing with the theme of armors designed for extreme environments, the "Starboost" was intended for near-orbit and space travel. Like the Hammerhead, the Mark XXXIX also had a supply of oxygen, as well as defenses against solar radiation and vast temperature changes found in the vacuum of space. The Starboost is also wholly unique for its white armor coloring. The suit may have been inspired by Tony's brief foray outside the atmosphere in The Avengers, which led to him losing consciousness. Though Tony never really used the Starboost, having the extra supply of oxygen would have certainly been helpful when he was stuck on the Milano with Nebula.

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Mark XLIV & XLVIII "Hulkbusters"

Hulkbuster versus Hulk in Age of Ultron

As a last line of defense against the MCU's behemoths, two versions of the "Hulkbuster" armors have been used to confront such monsters as an enraged Hulk and the Black Order's Cull Obsidian. Deployed from an external orbital station, the Hulkbuster armor could reconstruct itself mid-fight, allowing its user to take massive punishment without fear of destruction. Other than being incredibly resistant to damage, the suit mostly operated like any other Iron Man outfit, with the standard repulsors, flight system and HUD. It did also have a few tricks up its sleeve, such as a jackhammer arm similar to the Mark XXVI, grappling hooks and a canister of sleeping gas.

Mark L & LXXXV (Nanotech)

Doctor Strange and Iron Man Infinity War featured in the MCU

The only two suits to feature Tony's nanotechnology breakthroughs, the Mark L and LXXXV, were designed to adapt on the fly to almost any situation faced by Stark. Able to form almost on command and storable on Tony's body, the suit could also re-route its constituent nanites to rebuild damaged portions on command. One particularly impressive feature was the debut of melee weapons, specifically an arm sword, hammer and shield, made possible by the nanite's build capabilities. The Mark LXXXV was even shown to contain an Infinity Gauntlet, able to withstand the combined power of the Infinity Stones long enough for Tony's retaliation snap.

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