In the fourth episode of Marvel's What If...? Season 1, Doctor Strange pushes his ethics and skills to the limit to prevent the inevitable death of his girlfriend, Christine Palmer. To do that, he travels to the library of Cagliostro and learns of ways to obtain power through the Dark Arts. As a result, he is changed, and he inadvertently brings about the end of his entire reality. While the concept is terrifying to think about, it's even more frightening to consider that this reality's Strange could be equal to -- if not exceed -- the power of the Infinity Gauntlet.
In Avengers: Endgame, a time-displaced Thanos boasts that he plans to take the Gauntlet and erase all existence rather than merely half. Once accomplished, he would recreate all life in his image so that no one can challenge him. While it would take an enormous amount of energy to do, it is definitely possible with the combined strength of the Infinity Stones. On top of that, the Infinity Gauntlet was already been proven capable of bringing life back once it's been eradicated. That's because the stones are concentrated ingots made of the same energies found in the Big Bang. Therefore, their combined might is nearly limitless. That said, Doctor Strange Supreme demonstrates how much more power he has amassed and how he can challenge the Gauntlet.
What If...? Showed Doctor Strange at his Most Dangerous
Because it isn't easy to achieve the same level of power that What If...?'s version of Strange did, it's important to understand what makes him such a threat. Because love and the desire to beat the odds motivate this version of the sorcerer, no limits were keeping him from his goal. As a result, he could absorb the powers of some of the most magical and archaic beings in all of his dimensions. But, unfortunately, while his strength grew, his humanity began to fade as the power corrupted him.
By consuming so many magical beings, the fabric of reality began to fade away into inky blots resembling a lava lamp. In the end, Strange achieved his goal of saving Christine but doomed all of reality in doing so. Compared to the Gauntlet, Strange achieved the same goal as Thanos wanted but messier. That said, if he were to understand what his powers were causing before it was too late, he could have manipulated his universe-ending abilities to his advantage. In essence, he would be similar to Dormammu in strength, who thrives in the realm that Strange was borrowing energies and spells.
But what makes this version of Doctor Strange even more threatening than the Gauntlet and Dormammu is that he was stealing power from entities potentially as old or older than the Infinity Stones. This means he could even steal enough ancient power to overthrow the ruler of the Dark Dimension. If that were possible, Doctor Strange Supreme could potentially wipe out the multiverse with enough practice. Thankfully, his story ends before he can reach that level, with him locked away in a protective bubble, and forced to live with the consequences of his decisions.
What If...?'s version of Doctor Strange shows his destructive potential had he lost something more than his hands. But what's more terrifying is that his potential could end all of reality. Had he grown more powerful, he could have been affected even more. During The Infinity Saga, it was believed that nothing could top the destructive force of the Infinity Stones. However, the multiverse has shown that there is always something or someone more powerful.
What If ...? Season 1 is available to stream on Disney+.