Correct me if I'm wrong, but I believe it gives you 7 items that spin around you, and when you press the item button again, it activates which one is in front of you, so if it's a mushroom, you'll get the boost, but if it's a shell, you'll fire it.

I'm pretty sure that's what the Lucky 7 is. (I think it's called Lucky 7?)

The lucky 7 is like having 3 shells spinning around you but instead you get Green Shells, Red Shells, Bananas, Mushrooms, Stars, Blooper and Bob-ombs.

The really neat thing about the 7 is that if the rule set only allows one item, you'll get 7 of that item.

I think it gives you all 7 items there is. except i dont think it gives you the blue shell but every other item it does. And they took out the trap box, the pow block and the lightning cloud items

so to recap everything the Lucky Seven gives you 7 items which spin around you like green shells.

These 7 items are (1 of each):

Mushroom
Star
Green Shell
Red Shell
Banana
Blooper
Bob-omb

If you press the item button (X/Y/R iirc, i only use R), the item in front of you will be used. If somebody rams into an item, it acts like it was liying on the track. So if they run into the star, they 'steal' the star, but if they run into a green shell, they just trip over and lose 3 coins.

This item is actually pretty good in getting in a better position vs the cpu, because of the star, mushroom, red shell and blooper. This is also the reason why wou can only get it when you are around being 7th while getting an item box.