The Marvel Universe has no shortage of incredibly powerful beings, known colloquially among the fandom as cosmic-level entities. These include Galactus, the Silver Surfer, and other entities like Death and Eternity. Among the many hyper-powerful beings are the Celestials, of Eternals fame; these creatures shaped the past of the universe and can live for millions of years. But one solitary Beyonder from the Secret Wars series can defeat every single one of them...with worrying ease.
In the original 1984's Secret Wars, various heroes and villains are brought together on a patchwork arena known as Battleworld by the mysterious Beyonder. "I am from Beyond! Slay your enemies and all you desire shall be yours!" the Beyonder says. In the series, Doctor Doom manages to take the Beyonder's impressive power...only to lose it at the end. But what if Doctor Doom kept the Beyonder's abilities? Such is the question posed in What If...Secret Wars Vol #1, and if Doctor Doom was powerful before, the abilities of the Beyonder grant him virtually unlimited potential.
In this What If? story, Doctor Doom survives the events of Battleworld with the Beyonder's power. The Beyonder is a massively-powerful reality warper, able to eliminate armies with a single thought, reshape planets and speak telepathically to multiple people at once. Though Doctor Doom is unfamiliar with the powers, he learns quickly, and eventually defeats nearly every opponent on Earth in an astounding amount of time. Wakanda, for example, falls in less than an hour...and that was only the beginning.
Doctor Doom uses his reality-warping abilities to attack the powerful Celestials - all of them - and miraculously defeat every other cosmic being. The battle exhausted him and took over four-hundred and seven years, but the Celestials are all dead by the hands of Doom. However, Doctor Doom isn't used to the powers of the Beyonder at all...and the Beyonder from whom Doctor Doom stole the power was only a child of its species. An experienced Beyonder could most likely accomplish all of Doctor Doom's feats with ease, and in considerably less time.
It is fortunate, then, that the Beyonders mostly keep to themselves within the Marvel Universe. They wield nigh-omnipotence and their only weakness is their inability to travel through time. However, with Doctor Doom's technology, he could easily overcome this, and with the powers of the Beyonder, could take over the universe as easily as he did in this memorable What If? tale.