- "They don't like us very much in there."
- ―Zak Monday
The Smoke Mirror is an ancient Aztec artifact imbued with dark magic, the main function of which is to act as a viewing mechanism, and a portal, into a polar opposite anti-matter universe. The mirror appeared several times throughout the universe with the introduction of the Mondays.
The mirror may only function as a portal when two of the same objects from each side, such as Zak Saturday and Zak Monday, are present near to the mirror.
The anti-matter universe on the other side of the mirror is dark and dystopian where the Mondays are loathed as criminals. Everything functions as its parallel opposite: Zak Monday is cruel and psychotic, and boastful with it, Doc Monday is a brutish fool, Komodo Monday is an evil genius who can talk, and the Airship is powered by darkness, rather than sunlight.
The laws of matter and anti-matter function somewhat differently in the Saturday universe (though this may be the magic of the mirror affecting the science.) In reality, any form of anti-matter coming into contact with any form of positive matter causes instantaneous annihilation and a 100% energy yield (Typically resulting in explosions some 20 times or more powerful than modern nuclear weapons). In the Saturday universe, two opposing people or items must come into close proximity for irregularities to occur, again such as Zak Saturday and Monday.(This may be a result of the mirror's magical properties, as the mirror would be useless if it destroyed itself and its user). At this point, the laws of physics begin to break down, causing the environment around the two people or objects to warp and distort, and if the objects or people in question come into direct contact, they drag themselves and any immediate surroundings into oblivion. The warping of reality will occur even without the counterpart present if the amount of material is great enough, and will cause wide-scale chaos, as seen in "Paris is Melting".
When first seen, the smoke mirror allowed for the Mondays, the Saturday's opposites, to escape into the positive matter universe and attack before being tricked back in.
In the second appearance, "Paris is Melting", Zak Monday and Komodo Monday escape again, and force Zak to retrieve their airship from beyond the mirror so that they can wreak havoc in the positive world. Zak does so, but tricks the two villains back into the negative universe by draining the airship's power supply and placing the mirror below as it plummetted from the sky.
In its final appearance, V.V. Argost used it to summon Zak Monday from the negative universe before murdering him and stealing his Kur powers.
- Apparently, there is no hot chocolate or marshmallows beyond the mirror.
- It's similar to the Rowdyruff Boys from The Powerpuff Girls.
- The Villains in that world (V.V Argost, Munya, etc) have never been seen. It is unknown whether their being polar opposites of the positive universe villains means that they would be good.