I hope it appears, that would be interesting

So im assuming this will grant an extra stock in stock mode, 1 free point in time mode, and about maybe 50 free coins in coin mode

In order for this to not be broken, it would have to be very rare, as rare as a Golden Hammer at least.

^This, but I don't see this idea happening sadly...
It just seems too broken, even with it being very rare...

Yeah that's way too broken. Not a good idea.

imagine your about to kill someone you both have 1 life and 150% damage and then bam random 1-up mushroom they get it and
your screwed

that's the point?

Uh... okay new subject. Seeing as how Nintendo has come out with a lot of games since Brawl, would you like to see any new stages from newer games, and if so, which ones?

idk there aren't that many brand new series' that i want to see implemented.
though miyamoto said he had a bunch of cool new IP ideas for the wii u, so maybe they'll show up in smash 4?

What about from the existing series' newer games, like Skyward Sword and Super Mario Galaxy 1&2?

Like I said earlier, I firmly believe Ghirahim will be playable. I can find my paragraph of reasoning if you really want but eh.

Galaxy will be the theme for mario's main new stage, replacing Isle Delfino, replacing Peach's Castle, replacing the other Peach's Castle.

I'd love some representation from Metroid prime 3: Corruption, but it seems more likely that Other M will be getting all of the glories. Speaking of Metroid I'd love to see Ridley in.

Do you think the 3DS version and the Wii U version will have stages that are unique to each of them?

i will literally stab myself in both of my eyes if ridley is playable (he won't be)
Rundas on the other hand would be super cool. Gandreyda and/or Ghor would probably be fine as Assist Trophies but I doubt they'd be more than that.

No clue. We still have to wait and see what Sakurai has to say about the two different versions. We have no way of knowing at this point how different/separate the games will be.

And have 3DS-WiiU stage transfer?

That would kinda ruin the exclusiveness of the 3DS and Wii U, wouldn't it?
Knowing Sakurai, he'd probably make them so different, that if you had a 3DS and wanted a particular feature that's on the Wii U version, you'd have to buy the Wii U. Then again, you could always play it at a friend's house.