What is a purple unicorn?

Excuse me, but could you please clarify what you mean by "a purple unicorn"? As far as I'm aware, unicorns are mythical creatures that are typically depicted with a single horn on their forehead and a coat of white fur. The concept of a "purple unicorn" seems to be somewhat unconventional, as unicorns are not known to exist in any color other than white in traditional folklore. Could you possibly be referring to a specific artistic depiction or cultural reference that incorporates a purple unicorn? If so, I'd be happy to discuss it further. Alternatively, could this be a metaphor or analogy for something else entirely?