The ultimate swiss army knife

[Overfloater]

Fits comfortably inside a kit bag!

[Red Iron Crown]

It has a TARDIS-style secret compartment where you can safely store all your worldly possessions.

[cantab]

Its satnav also has the TARDIS-like ability to direct you where you need to be.

[Norpo]

Coin flipper feature; Automatically dispenses coins for making decisions.

(may require restocking, using ONLY Official Kerbal Army Knife Coins, not usable as legal tender.)

Edited December 31, 2014 by Norpo
what the hey is a "coin flipper flipper"

[RAINCRAFTER]

It has a machine gun because that's cool.

[LABHOUSE]

It automatically dulls its blade with frequent use!

(Now even faster than other brands or versions)

Edited January 1, 2015 by LABHOUSE

[captain_fiddlesticks_]

It has an unlimited supply of peanut butter when most needed!

[Vaporo]

It has a supernova containment unit! (Warranty void if used in the presence of an exploding star.)

[cantab]

It has a highly effective* itch scratcher.

*Claim is of effective scratching. Itch relief not guaranteed.

[RAINCRAFTER]

And this all works no mater how you use the knife!

[Duxwing]

It comes with an artificial general intelligence!*

-Duxwing

*Friendliness not guaranteed. Do not instruct to make paperclips.

[flashcactus]

You can threaten people with it!

[Overfloater]

Can make your clothes invisible!

[megatiger78]

will eat you if you touch it.....

[Overfloater]

...with your 3rd hand.

[worir4]

It can be used as a back scratcher ...

[RogueMason]

...provided you scratch its back first.

It can also act as an interstellar superweapon to neutralise pesky parasitic lifeforms that may or may not be taking over the galaxy.

Warranty void if fired. Life void if fired.

[Vaporo]

It has a built in time machine! (DeLorean sold separately.)

Edited January 6, 2015 by Vaporo

[Bill Phil]

It can go plaid!

AKA ludicrous speed.

[LABHOUSE]

It is not made in China!

[cantab]

It is a convincing liar.

[Bill Phil]

It can cut the cake that is a lie.

[Red Iron Crown]

It gives sound investment advice that reliably delivers solid returns.

[RogueMason]

It includes a nifty spectroscope.

[Starwhip]

Is it an actual knife yet?

It has a blade?

I don't think anyone did that yet.