Miracle Sort

Check whether the array is already sorted. If it is, return. If it isn't, do nothing and check again — relying on cosmic rays, hardware faults, or divine intervention to flip the right bits. Capped to a small number of "prayers" before giving up.

Reminding interviewers that "O(1) extra memory" is not the strongest property an algorithm can have.

Always. The expected runtime exceeds the lifespan of the universe by several orders of magnitude.