That's because he can't swallow people like Kirby does. Once you enter inside Kirby there is no going out, so Kirby could easily swallow everyone and be done with it.

the problem with battles like this, is that people only look in the perspective of the character that they want to win.
So it will never be fair.

Solve this. Kirby uses the warp-star to intercept a throw of Mjolnir and cause it to enter into the irretrievable void-beyond his tummy. After that he absorbs its powers and, as per usual, those powers are signifcantly amplified by his usual instant mastery of even its wierdest properties.

Now I don't know that Kirby would prove worthy of the Power of Thor, but hopefully he wouldn't; because by proving unworthy he MOSTLY LIKELY gets a version of suction that is enchanted so that only a mystically chosen few can resist, becomes a version of Stone Kirby that is actually made of freaking Uru, gains far swifter flight because Mjolnir seems to be the source of the telekinesis its wielder has over it, qualifies as magical so he can take out Superman, AND gets a cool looking little hat like normal. Least I assume Mjolnir's hat would be cool, it would be kinda anti-climatic if it didn't look cool...

Thank you! This is the best comment in here so far. People will stubbornly look at any loophole, any weakness, any strength on their character, and this argument will never be won or over. While Nintendo characters does have many OP abilities, they aren't perfect. They can be killed while being manipulated by the player on their respective game.

Don't know about that he absorbs the abilities of his enemies and uses them for himself, he can essentially take any opponent comic, game, first party peers, anime and all. If he has the intelligence of a genius I'd be scared for any opponent to stand in his way.

Actually, it's to do with his self confidence but he can acquire anyone's power just by being near them and the amount of powers he can have is limitless. He even can take their intelligence, fighting skills.

Basically, Mimic can copy Kirby's power to breath people in and copy their powers, without breathing Kirby in.

Depending on the source, when Kirby breathes someone in he gets an amped-up version of their powers. Does that mean that Kirby could gain an amped up version of his owner power if he swallowed Mimic? Also what happens to Mimic's version of Kirby's power if he swallows Kirby? Does Kirby's being that far away (inside) cause Mimic to lose Kirby's power? If so does Kirby pop back into real-space? Or does Mimic's Kirby copied copying of Kirby become a self-sustaining reaction?

Mimic does have a range but not sure one the continuity of that. It's mentioned as miles from the original being, the question should be whether inside Kirby  (pocket dimension right?) is miles from him or not. So Mimic copying Kirby's power than Kirby breathing him in would mean Kirby's power is greater, then Mimic's is and then Kirby's is, then Mimic's is....

...think we may be over thinking this.

The solution is simple; Kirby becomes the God of the outer dimension because he absorbs and wields the power of Mimic-Kirby-Mimic-Kirby-Mimic-reoccuring while Mimic becomes the God of the pocket dimension where all other heroes and villains now reside because he wields the power of Kirby-Mimic-Kirby-Mimic-Kirby-reoccuring.

You're the same person who said that no Nintendo character can beat anyone. I think you're most guilty of that.