The Old Improbable Island Wiki

Basically, probable is improbable without any im, the one ingredient that must be added to probable to make it improbable. Probability is an unstable force. If it is mixed with improbability, it will explode¹⁾, causing all people within a 50 foot radius to become like the Batman.²⁾³⁾⁴⁾⁵⁾⁶⁾

¹⁾

Or transform into a pink raincloud

²⁾

As such, it is not recommended to bring probability to the Island.

³⁾

Seriously, don't do it, man! It could throw the island into a war between the Batman race and the joker race that could destroy us all!

⁴⁾

Fortunately, kittymorphs, robots, and gobots will be immune to the explosion.

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Midgets and mutants, on the other hand, will also become members of the Batman race, due to their close relation to the human race.

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In the case of most mutants, this will be a good thing, realy.