digibutter.nerr

[Yoshi]

'Cuz Nintendo predicktable at that. (And yes, if you look closely enough at that sentance, I did that on purpose, but that's not the point.)
Most likely:

Bouldergeist: Throw bombs at him without losing three balloons

Kamella: Throw green shells at her without losing three balloons. She might shoot blasts that turn into item boxes after they've hit.

Dino piranha: I'm not sure how they'd do this one. It'd probably be a tough race in THERE'S A GIANT PLANT LOOSE IN COCONUT MALL! Peach gardens. It would cut past the off road, and jump over some parts. And all you have is a bunch of item boxes that give you stars. >.> Oh, right.

King Kaliente: I really don't know how they'd do that.

Firey dino piranha: Like the dino piranha above, but it's in grumble volcano. He "Accidentally" makes the ground break on the first lap, and leaves trails of fire. Here, you don't get stars, only golden mushrooms, so you're not invincible from the fire.
Less likely:

Garbage destroying: Never was a boss, but throwing bobombs at garbage. W00t!

The one killer whale thing in sea slide: Fought on koopa cape, you get a head start because he can't go fast on land, so he hops around, going about half as fast as you do. But when he's in the water, your head start is over, and he starts to really catch up.

Big bad buggaboom: Wind around a tree, and fall on bugaboom three times. >.> It's a very deformed tree.

Bowser: You can't use bowser as a character here. It would work like the fights do in galaxy, but you're in a kart.

Bowser jr: Can't use Bowser Jr. as a character here. He shoots bullet bills, and that junk at you. Use green shells on his ship to win.

Megaleg: While dodging bullet bills, get to the item box, and wind up the giant legs The item box is a bullet bill. Seing as you're in a kart, thus, can't jump, getting up to the top of megaleg is a HUGE challenge. Just use the bullet bill, it'll break the top off, and then you fall off. Rinse, lather, repeat. The bullet bill also won't work if you try using it to get ontop of megaleg.

Shadow your character: A challenging race on rainbow road three laps against a very challenging version of your character, who'll try bumping you off, and everything. They'll have the same kart as you, same character, but all their weight stat is at max no matter what. They'll try drafting you, and bumping into, just to ruin your time in any way they can. The largest threat is being bumped off, however. If you fall off, you'll come back on, only to see the shadow was wating for you so it can still torcher you. It's not just a matter of beating the shadow, (As near the end of the lap, it stops bothering you, and begins to race. An if you're funky on flame runner, they'll catch up to you, so don't even think about outrunning the shadow, unless you're a perfect machine. No items either. Just a race. They'll also imediately bump into you when you try to start a wheelie as to slow you down.

[King Harkinian]

Kingfin: Koopa Cape- race him. He's like Dry Bowser on a Dolphin Dasher.

Penguru: Yeah...the penguin from Bigmouth Galaxy. Race him in N64 Sherbet Land.

[Yoshi]

Koopa cape isn't emo enough fore kingfin. He's not likely to ever be shown.

And penguru isn't a bad guy. Unless, ofcourse, you're angry at him for making you get on the manta ray.

[King Harkinian]

[Yoshi]

[Greenlight]

[Ph1r3 Mario]

[Greenlight]