A dead shark.
The shark apparently made the trip downtown on the city's Metromover train, and yes, it had some help.
Local TV stations report that two men had been trying to sell the animal to at least three fish markets.
Apparently they were only asking for about $10, but an employee at the Casablanca Fish Market said his business doesn't "buy sharks off the street."
To take a bite out of this sort of crime, authorities say the incident could lead to misdemeanor charges of improper killing and disposal of an animal, and selling a shark without a license.