An Orange Bicycle is a mythical object in the Aeldrum universe.
No man or being would be able to even conceive of, much less obtain, an Orange Bicycle without suffering instant insanity. The lack of Orange Bicycles is partially due to the non-existence of rubber trees in the entire universe. This in turn means that there are no rubber tires which can be used to construct an Orange Bicycle.
To even conceive of a normal bicycle is to instantly go mad. Furthermore, Orange is the color of madness. This combination is therefore even more impossible. Similarly, to conceive of a unicycle is to only go half mad.