Bunny (Mario's Time Machine)
From the Super Mario Wiki
The Bunny is an item in the PC release of Mario's Time Machine. It is one of the rabbits that Louis Pasteur has successfully vaccinated, and it is now completely healthy. Mario receives from Pierre Paul Emile Roux after traveling back in time to Paris in 1885. The Bunny can then be given to a nearby tailor, who had previously mentioned that he wants to give his daughter a rabbit as a gift. Mario then gives him the Bunny in his possession, and the tailor recognizes it as being one of Louis' rabbits since it looks healthy and Louis is known for taking good care of animals.