Anyone wanna play game designer with me?

While playing Mario Kart 8 (a fantastic game!) a few of these came to me.

1. Traffic Jam: Your character is presented with a giant jar of grape jam.  When you use the item you leave jam behind in your wake. Drivers coming across the jam will experience severe slow down.  Perhaps throwing the jar at another driver will slow them down and obscure their view like the blooper.

2. Petty Theft: As you bump into another kart you steal whatever item they have.  This would also work if they bump you while you have the item.

3. Tether: Using this item would link your kart with another for a brief period of time via a rope.  This could either slow them down or speed you up, depending on their power and momentum.  Any riders caught mid stream as it were will also be clotheslined.

Thoughts?  Any other ideas?

Yes. In the form of a Boo (ghost) item that would steal opponents' items and give them to you.

OT: The traffic jam thing sounds pretty fun, but translated into any other language but English it wouldn't make sense.

I call it the Fake Item Box or FIB for short

I never cared too much about the FIB, but I wonder why Nintendo didn't put it in MK7 and MK8!

Yeah but it's better than the coin. It's also really balanced. It's still that item that can't block incoming attacks but at least it can be used to attack. Giving racers what is basically nothing over and over now is frustrating 😤 

Not Nintendo enough. The basic concepts are fine, but the details don't feel like a Nintendo game's details.

For 2, how about Nabbit? Use the item, and Nabbit will dash out, looking for the nearest character with an item. Upon finding one, he'll grab it, and start running back to you. He can be intercepted by other drivers, though.

Rather than "traffic jam", which is a good pun but not really matched to Mario, how about Micro-Goomba, which results in a heap of mugger micro-goombas dropped on the track - when touched by a kart, they latch on, slowing the kart down. If the driver is bumped by another driver, the micro-goombas can transfer over.

For "tether", maybe "Lakitu's Rod", which is basically a fishing rod that players can cast towards other karts, and perhaps even structures on the course (so it could be used, not just to tether to another kart, but also to, for instance, use the slingshot effect to gain speed by latching onto an object in the middle of a course).

Another idea would be to have "Poltergust" as an item - use it to create a vacuum effect, pulling your kart forward and slowing anybody nearby in front of you, and also pulling in coins, banana peels, shells, micro-goombas, etc (you don't actually collect the pulled-in items, they get "destroyed").

An "Ice Flower" could bounce along the track in front of you, momentarily freezing any other driver it encounters (causing them to skid forwards, which could cause them to go off track, or miss jumps, etc)... but it also leaves patches of ice on the track along the way, which means you now also have to dodge those patches of ice. And of course, it could bounce off something and you could still hit yourself with it. It would be a single-fire weapon.

One more... how about a "Metal Cap", turning the player in a metal version of themselves, significantly increasing their weight and causing any racer they bump into to spin out on contact. Reduces acceleration but increases temporary top speed (streamlining).