Kryptonite

Kryptonite is an infectious hazard appearing as crystalline substance or mysterious energy.

=In fanon games=

In Pikmin: Ultimate Doom
Kryptonite is a very powerful essence that originates on Duron's moon, Krypton. Its power is almost unlimited, and it is not a solid, liquid, or gas, yet it can flow about them. The object or being containing kryptonite is called its host. Kryptonite can drive those afflicted by it insane, but if channeled properly, can be controlled.

Kryptonite was created soon after Pikmin: Global Breakdown by many mutated organisms that migrated from the Distant Planet. One of the organisms was the microscopic lifeform that controls Mitites and became mutated when they were exposed to a volatile compound. Due to the controlling nature of the organisms, they took in the compound and began to encase any object that they touch in kryptonite. Soon the organisms became one with the kryptonite, retaining the controlling nature by becoming an essence and engulfing anything it comes in contact with.

The first time kryptonite was encountered by Olimar and the other leaders was in Pikmin: Ultimate Doom. The kryptonite made every kind of Pikmin insane, and no matter how much Olimar whistled at them, they wouldn't listen. Then the kryptonic Pikmin spread their affliction to as many Pikmin as they could. Soon Olimar's despair is over when he finds Grey Pikmin in Dark Moon's dungeon, Inclement Night. The Grey Pikmin are impervious to kryptonite and can cure kryptonic Pikmin and captains.

When Pikmin come in contact with kryptonite, they begin to glow lime green and run around frantically. After ten seconds of panicking, kryptonic Pikmin settle down and hunt non-infected Pikmin and enemies to spread their affliction. If a kryptonic Pikmin or kryptonite touches a leader, they also attempt to spread the affliction. If every leader is infected, a game over will occur, and the day will automatically restart.