In the world of Dragon Ball, Goku has defeated virtually every opponent bold enough to face him, but he’s never fought an entity quite like Marvel’s Galactus. This begs the question - could Kakarot defeat the Devourer of Worlds, or is Galactus simply out of Goku’s league?
As one of the last remaining members of the Saiyans, a powerful alien race, calling Goku a rare breed would be an understatement. However, while his base abilities like super strength and flight come from his Saiyan roots, Goku’s true greatest power is his determination. Through rigorous training, Goku has perfected countless martial arts techniques, making him an incredibly skilled fighter, and he’s even proven that he’s strong enough to escape a black hole's gravitational pull. Just when it seems like he’s reached his limit, Goku evolves into a new, more powerful form. In fact, Goku has so many different transformations at this point that it’s almost hard to keep track of them all. From the Kaioken technique to Super Saiyan Blue, Kakarot has plenty of tricks up his sleeve, but perhaps his ultimate trump card is the form known as Ultra Instinct, which is even stronger than super saiyan. While in this form, Goku was able to beat Jiren, who was said to be even more powerful than the Gods of Destruction, but would it be enough to take on Galactus?
Know as the Devourer of Worlds, Galactus is a cosmic entity as old as the universe itself, and widely considered one of Marvel's most dangerous villains. While different stories have varying depictions of the world-eater, Galactus is generally portrayed as a gigantic humanoid decked out with alien technology that allows him to absorb the energy of entire planets. However, his greatest weapon is known as the Power Cosmic, an energy source of almost immeasurable power. With the Power Cosmic, Galactus has telepathy, telekinesis, energy projection, teleportation, and more. At the height of his powers, Galactus can even transmute matter, meaning he can literally manipulate reality. As powerful as he may seem, however, Galactus and Goku are far closer in strength than meets the eye.
On paper, Goku can do almost everything Galactus can - he can fly, project and redirect energy, teleport, etc. His biggest disadvantage would be his much smaller size, but Marvel has shown that characters like Thor and Hyperion can actually defeat Galactus with relative ease. Galactus may have immense power, but he needs to constantly feed on planetary-levels of energy to sustain it. Goku, on the other hand, often reaches his most powerful form when he’s at the very end of his rope. So while Galactus would get weaker as the fight went on, Goku would get stronger, giving him the edge.
As with most versus scenarios, the outcome of the fight would largely depend on circumstance. Taking on the Devourer of Worlds at full power probably wouldn’t end well for Goku, but if a hungry Galactus came to his world looking to feed, there’s a good chance Goku could beat him back.