There are a good number of inventions and ideas from Iron Man, there were elements of his Avenger journey and creations that were less than ideal. While most inventions from Tony Stark begin with good intentions, some had pretty brutal consequences nonetheless.
Beginning with 2008's Iron Man, Tony Stark has been a core foundation of the MCU with multiple Iron Man appearances. In that entire 11-year span ending with his ultimate sacrifice in 2019's Avengers: Endgame, Tony Stark came up with plenty of inventions and ideas, and he even helped create new heroes. However, there were often unintended consequences that were created as well. Some of these inventions even blew up after his demise, negatively impacting his legacy instead. Here are 8 of the biggest times in which an invention or idea from Tony Stark had unintended consequences.
8 Hall of Armors
Although the initial invention of the Iron Man armor was a good one, Tony Stark couldn't stop building suits. Especially following the trauma he experienced during the Battle of New York, Iron Man 3 revealed that Tony Stark has been continually building different suits of armor rather than dealing with the actual problem he was facing. Terrified of losing those he cared about and wanting to protect them at all costs, Stark nearly lost Pepper Potts, motivating his decision at the end of the film to blow up his entire Hall of Armor as it had become a crutch.
7 Ultron
Despite blowing up the Hall of Armor, Tony Stark continued to fear the future while carrying the desire to create "a suit of armor around the world". Following the manipulations of the Scarlet Witch, Tony made the unanimous decision to create the AI known as Ultron using the Mind Stone as a key element. However, Ultron was born rogue, believing that peace for the world meant the end of the Avengers and humanity itself. As such, the creation of Ultron in turn created a cascade of events that would ultimately lead to the Avengers' division in Captain America: Civil War and a lack of protection for Earth in Infinity War.
6 Vision
Receiving help from Bruce Banner and Thor, Tony Stark created the synthezoid known as Vision as a means to combat Ultron. The Vision was created using the Mind Stone and a combination of algorithms and personality matrixes derived from Ultron, Stark's AI assistant JARVIS, Banner, and Stark himself. Although he played a key role in Ultron's defeat, the unique nature of Vision as a sentient and free-thinking being had its consequences in the MCU as well.
This includes the Vision inadvertently injuring Stark's best friend Rhodey during Civil War, seeing as how he was distracted due to his new love for Wanda Maximoff's Scarlet Witch. Likewise, Vision's existence and integration of the Mind Stone made the Avengers' mission much more complicated when Thanos and his forces arrived to collect all the Infinity Stones, arguably leading to the Mad Titans' victory with the Decimation. Vision also motivated Wanda's eventual corruption due to her grief over his death. While the Vision has done plenty of good following his creation, there have been undeniably heavy consequences as well.
5 Damage Control
Originally, The Department of Damage Control was a t venture between the US government and Stark Industries to collect and clean up the alien tech and remains left behind in the fallout of the Battle of New York. However, this inadvertently led to the creation of Adrian Toomes' Vulture who took his out-of-work salvage crew and turned it into a black market weapons ring, keeping the alien tech for themselves. Additionally, the DODC would later expand its authority into the observation and detainment of superpowered individuals. To that end, some agents have taken more aggressive liberties in the detainment of said individuals as notably featured in Ms. Marvel.
4 Iron Spider Suit
It can be argued that Tony Stark's mentorship and effective creation of the official Spider-Man in the MCU had its drawbacks. Case in point, Tony Stark introduced a whole new source of responsibility, stress, and guilt in his life in his desire to protect Peter Parker while guiding him to become a great hero. However, the invention of the Iron Spider suit particularly blew up in Tony's face as it allowed Parker to him in his Infinity War mission to the planet Titan, helping take down Thanos when Iron Man would have preferred that Spider-Man stay home where it was safer.
3 Quantum Time-Travel
Five years into the Decimation and the erasure of half of all life in the universe, Tony Stark was approached by Captain America, Black Widow, and Ant-Man for his help to devise a means of time travel to go back and save those they'd lost. Not wanting to risk the family he'd built in the years since The Snap, Tony initially declined but couldn't help himself once his fellow Avengers left. Eventually figuring out how to successfully time-travel through the Quantum Realm, Stark regretted his invention almost as soon as he made it.
Knowing all too well the risk that would be involved, Stark was still compelled to try and save those who'd been lost all the same. Sure enough, Iron Man's invention of time travel directly led to his demise with the Infinity Stones. Although he saved the universe, the cost was his own life after realizing it was the only way Thanos and his forces could be defeated.
2 Nano-Gauntlet
The same aforementioned consequence can also be attributed to Stark's nano-tech armor and the gauntlet he created to house the Infinity Stones. Because he was the only one who could successfully transfer the Infinity Stones from the gauntlet in Thanos' hand to his own armor, Tony Stark was the only one who could save the universe. As such, the nano-tech ensured that Iron Man had to sacrifice himself, albeit for the greater good and those he loved. Of course, Tony Stark would've preferred to have lived, and he said as much at the beginning of Avengers: Endgame.
1 EDITH
Attempting to leave a legacy and effective inheritance for Spider-Man in the event of his death, even Stark's EDITH glasses had unintended consequences that ultimately harmed his legacy overall. Standing for Even Dead, I'm The Hero, the glasses Tony left for Peter Parker granted him access to Stark Industries' global satellite network along with an arsenal of missiles and drones. However, the power was too much for Peter who felt it would be better in the hands of Quentin Beck's Mysterio, not realizing that Beck was actually a disgraced Stark employee leading other disgruntled employees who'd been using AR to make him seem like a hero.
Following his defeat by Spider-Man, the Stark tech from EDITH helped Mysterio publicly expose Spider-Man as Peter Parker and paint him as a murderer. It also allowed the DODC to claim all the drones and tech in the aftermath, using them with extreme prejudice against superpowered individuals. Naturally, this is something Tony Stark likely would have never wanted, especially in regard to his legacy in the MCU.
