The combatants:
 

The referee:

The announcer:

***

Boo: Boo ha ha! Good evening, and welcome to the first battle at Roy's Boxing Arena! I'm Boo, and I'm glad to-

Roy: (while throwing "practice" punches at Paragoomba) Get on with it, or I'll get a new announcer!

Boo: Yes, of course!

Lemmy: (from the audience) Uh... I don't think you should be punching the Paragoomba before the bell rings.

Roy: I'll punch you next!

Lemmy: Koopa Troopa!

Koopa Troopa: I didn't see anything...

Roy: Boo, quit stalling!

Paragoomba: Yes, please. Ouch!

Boo: Ok ok! In the red corner, weighing in at a number of pounds so hihh and scary I can't even say it, the honorary champion, and a champion at heart, that frightening prizefighter, Roy Koopa!

Roy: (waving his arms wildly while kicking Paragoomba) Thank you! Yeah, you got it right!

Boo: Heh heh! This next guy is so pathetically feeble that it scares me! In the blue corner, weighing in at three pounds take two, that scumbag of the arena and my favorite boxing bag, Paragoomba!

Paragoomba tries to wave to the audience, but he is heavily forced aside by Roy, who is still greeting the audience. Koopa Troopa beckens the two fighters to the center of the ring.

Koopa Troopa: Ok, ya'll both know the rules... or at least I hope ya do, cuz I don't know 'em! Let's have a nice clean fight and... uh... any of you got a beer?

Roy: (whispering to the Troopa) Make sure I win, and the beer's yours.

Koopa Troopa: Ya got it!

Boo: I'm excited out of my wits! Let the battle begin!

The combatants are back in their corners. Ten minutes pass. Finally, the bell sounds because Koopa Troopa drunkenly fainted into it.

Roy: I'm gonna pulverize ya!

Boo: This is incredible! Roy is tearing up the floorboards on his way to that weakling Paragoomba! No, he's not running, but it's his great weight. Oh, I wouldn't want to be the Paragoomba today, or any day!

Paragoomba tries to fly out of Roy's range, but-

Paragoomba: My wings! They've been super glued to the floor!

Roy: Ha ha! Them's the breaks, and I'm gonna break them off! Nice work Troopa!

Koopa Troopa: Wuh? Uh... zzz...

Roy reaches Paragoomba and starts slamming him with both his fists. The Paragoomba is instantly knocked senseless.

Boo: Oh, what power! This is a truly hair-raising experience... too bad neither of them have hair! Oh look, Paragoomba's wings just fell off! Well, you know what they say... uh, what do they say?

Roy: (still punching) DIE!!!

Goomba (no longer Paragoomba since his wings are gone): ...Ow...

The Goomba becomes unconscious, but it doesn't stop Roy.

Koopa Troopa: Mommy, I don't want to go to school!

Lemmy: Stop this! Roy, you won! Enough all ready!

Roy (laughing and still punching): Aw, is Lemmy squeemish? Ha!

Boo: It looks like Lemmy is squeemish, and I know I would be if I were on Roy's bad side!

Lemmy: No more! This is my Land, and I say the fight's over.

Roy: Dang it Lemmy! Ah fine, have your dumb Paragoomba, see if I care. I'll get you!

Lemmy: Yeah, I'm real scared.

Boo: And the match is over! Your winner and still champene, the best fighter in the Land, the one that no one sane would dare stand up against, the wall, the krusher, it's Roy Koopa!

Roy: Thank you!

Koopa Troopa: (awakening): Is... is it over?

Roy whispers something in Koopa Troopa's ear.

Koopa Troopa: Wuh?

Roy whispers again.

Koopa Troopa: Huh?

Roy shouts as loud as he can at Koopa Troopa. Miraculously, no one else hears.

Koopa Troopa: Ah, ok! Uh, k ya'll! There's a new rule, and it's that the champion gets to pick the next entropy.

Roy yells at Koopa Troopa again.

Koopa Troopa: I mean enemy! Yup, so Roy, who ya want to battle next?

Roy: I'm gonna make mincemeat out of Lemmy!

Lemmy Koopa: ...Uh oh...

Boo: And there you have it! Be sure to get your tickets early and be here next time when Roy creams... er, I mean, goes up against Lemmy Koopa for the title of Ring Champion. I'm afraid to miss it!

The winner:

The loser:

Now you have a choice:
You can go back and memorize the rest of the battles.
You can go back to the boxing arena, because I know you loved it so much!
Anyone who rats about the conditions here will be personally pounded by me! If you'd like a pounding, you can also go back to Lemmy's Land.