What If...?'s Season 1 finale on Disney+ featured a team-up of a few of the characters that previous episodes introduced into the MCU. At the beginning of the episode, The Watcher bounced around from universe to universe to recruit the likes of Captain Carter, Party Thor, Star-Lord T'Challa, and the Killmonger that saved Tony Stark.
The Watcher also brought along someone new to the team when he visited Nidavellir, the place that Stormbreaker was forged in Avengers: Infinity War. Tony Stark and Gamora were in the process of melting an Infinity Gauntlet from their universe when The Watcher showed up and told Gamora that she had been chosen, just like he had told the other characters.
This version of Gamora sported gold-colored armor that looked almost identical to the armor that Thanos wore during his quest to find the Infinity Stones in Avengers: Infinity War and Avengers: Endgame.
The new team members were then put together for the first time in the series as the Guardians of the Multiverse, and then The Watcher informed them that their mission was to stop an Infinity Stone-powered Ultron who was destroying world upon world.
Knowing that the Infinity Stones are a force to be reckoned with, the team struggles to figure out a plan for destroying Ultron. That is until Gamora reveals a weapon that she used in her world to completely destroy the Infinity Stones, a gadget that she referred to as the Infinity Crusher.
The Infinity Crusher in What If...?
Just before Gamora revealed the Infinity Crusher to the team in the Season 1 finale of What If...?, Thor asked, "How would you even go about destroying the... Oh, you're answering my question, sorry, thank you."
Gamora then pulled out the gadget, which had two handles on each side and then what looked like a grinder in the middle. She then responded to Thor by saying, "The Infinity Crusher. Designed to disintegrate each Stone into nothing."
The Crusher also had an octagon-shaped opening at the top, and while Gamora didn't specify what that part was used for, it could be assumed that one of the Stones would be placed there.
Ready to take on Ultron, the team set out on their mission, which was, in Captain Carter's words, "Get the Soul Stone and get it to Gamora. We'll hold the line, and then she'll unleash The Crusher." After a brief fight with Ultron due to Thor's ability "to attract unwanted attention," they are able to steal the Soul Stone from him and go through a portal to another world. Before they can use the crusher to destroy the Soul Stone, however, Ultron shows up again as another fight ensues, this one much harder on the Guardians of the Multiverse than the last.
After battling Ultron and ultimately pinning him to the ground, Gamora is able to place the Soul Stone in the octagonal figure atop the Infinity Crusher. Then, the weapon comes to life and sprouts six legs, running over to Ultron as he is lying on the ground with the remaining five Stones still in his armor.
The Infinity Crusher in Action
The Infinity Crusher then quickly makes its way over to Ultron, crawling on top of him and positioning itself directly above the remaining Stones on his chest. As it activated the circular crusher in the middle of it, an arm popped out to grab onto the Mind Stone that was on Ultron's head.
As the Infinity Crusher worked on destroying the Stones, it looked as though it was ultimately successful, as an enormous energy blast was emitted, leading the heroes to believe that they had won.
Seconds later, Ultron emerged from the rubble that the blast created, stating that "Every universe is different, each one just a fraction unique. Thus, the Infinity Stones are unique." Gamora instantly realized why the Infinity Crusher didn't destroy the stones, clarifying that "The Crusher was designed to destroy the stones on my world, not his."
The Guardians of the Multiverse then had to think of another way to defeat Ultron, with Black Widow ultimately shooting an arrow into his eye. This planted the Arnim Zola virus that was seen in Captain America: The Winter Soldier into Ultron, ultimately taking him over and defeating him.
The story didn't end there, however. Killmonger walked over to where the Stones were and forged his own version of the Ultron armor before the Zola-controlled body of Ultron began fighting him for the Stones. Strange Supreme ultimately ended up locking the two in a sort of prison using the Mystic Arts, where they remained even after the episode ended.
The idea of introducing a weapon like the Infinity Crusher that can literally crush the Infinity Stones into nothing is interesting, mainly because of one reason, and that reason has to do with a specific unanswered plot point from Avengers: Endgame regarding Thanos.
Did Thanos Have an Infinity Crusher?
Many fans were probably shocked as they sat in the theater to watch Avengers: Endgame for the first time. In the first act of the film, the remaining members of Earth's Mightiest Heroes find the planet Thanos was living on after he snapped away half of the population, and they devise a plan to go and attack him one last time.
When they got there, however, Thor chopped Thanos' arm off with Stormbreaker, and Rocket turned over the Infinity Gauntlet to find that there were no Infinity Stones. After Bruce told Thanos that they knew he had only used the Stones two days prior, The Mad Titan responded by saying, "I used the Stones to destroy the Stones," leaving it a mystery for both the Avengers and the audience as they wonder how he could have possibly done that, and if he was even telling the truth.
With What If...? introducing the Infinity Crusher into the MCU, the possibility that Thanos created the same kind of weapon is now on the table. He did also say that the Stones were "reduced to atoms," which would perfectly line up with how the Infinity Crusher actually destroys the Stones.
If the Crusher uses a Stone (the Soul Stone) to rip the remaining Stones from their resting place (in either an Infinity Gauntlet or a chest plate) and then grinds them down into dust, Thanos would have to have used a similar, or even the same weapon.
It is possible that Thanos could have used the actual Stones on each other, such as the Power Stone, but then once all the others were destroyed, how would he have reduced that one to atoms? Thanos is extremely strong, but even he is nothing compared to the power of the Stones. If they could be destroyed without the help of an Infinity Crusher-like weapon, they wouldn't have the reputation that they have throughout the universe.
The Infinity Crusher's Blast Almost Killed Thanos
Another piece of evidence that alludes to Thanos using an Infinity Crusher to destroy the Stones is how the destruction of them affected him. When viewers saw him for the first time in the Garden in Endgame, one side of his body looked as though it had been badly burned. He only had the use of one of his hands, and the side of his face also looked severely injured.
This strongly supports the theory of Thanos using an Infinity Crusher because of the blast that was emitted in Infinity War when Wanda destroyed the Mind Stone, ultimately killing Vision. When the Stone shattered, a huge wave of energy and radiation came from its destruction. It didn't harm Wanda, nor Thanos, but that could be because it was only one Stone.
Imagine not one, but all six of the Stones being destroyed at the same time. From the way the Infinity Crusher operates, it pulls all the Stones into its grinders at the same time and continuously crushes them. If all six Stones were crushed at the same time, especially while they were either on Thanos' arm or right in front of him, the blast would most definitely be damaging to him.
Even though the blast from What If...? came from Ultron, it is likely that the destruction of the Stones would look somewhat similar, only with more power. When Bruce put the Gauntlet on near the end of Endgame to bring everyone back, the gamma radiation that ran through him was enough to have a similar effect as it did on Thanos.
However, Thanos put on the Gauntlet with all six Stones multiple times, and it never had that effect on him, so it is almost a guarantee that he had to use some sort of weapon to destroy them.
It is interesting that Marvel Studios would introduce a weapon in What If...? that has the sole purpose of destroying the Infinity Stones, especially since they never clarified how Thanos destroyed the ones he used in Endgame. There are simply too many parallels between the two to ignore the theory that he had an Infinity Crusher of his own.
Will there ever be a concrete answer to the question? Probably not, but all the signs point to Thanos using a weapon that is at least similar to the Infinity Crusher, which would answer both how he destroyed the Stones, and how their destruction almost led him to his death.