1) The piano
This piano essentially ruins the musical experience for anybody who plays it. Although this piano gives one the ability to recreate any musical piece from memory, this piano also causes any person who plays it to be unable to compose new work or listen to any music that they don't create with the piano itself.
Those who play the piano report that any music heard after that point sounds unstructured: they report hearing random tones and rhythms instead of what is normally heard. It effects everything from a commercial jingle to a person singing by themselves to full in person orchestras - after playing the piano, one can no longer listen to music.
Those who listen to others play the piano report the player is simply playing in some random, unstructured fashion, however the player will report that they recreated a composition perfectly from memory.
While the piano has no direct effects other than that which was described, many exposed to the piano develop psychotic and obsessive symptoms surrounding the piano. It is thought that the stress of constantly hearing unstructured music is what causes psychotic reactions, not interaction with the piano itself.
This effect is independent of musical fluency, however those with technical musical knowledge are able to describe their experience in more detail, revealing details such as the ability to create non 12 tone songs on the obviously 12 tone keyboard of the piano.
The piano was recovered with a human female after reports of noise complaints. The female shows intense signs of paranoia, psychosis and obsessive behavior. Any attempts to interview the female result in her continually demanding to be allowed to play the piano. No information about the piano, nor the subject herself, has been extracted from the female.
With this I plan to get very technical and scientific; there will be many attached studies and experiments. I also plan to expand greatly into the technical explanations of what the piano is capable of, which will basically be anything, with careful attention given to examples that make no physical sense considering the construction of the piano (for example, being able to play 24 tone songs on the 12 tone keyboard). I also plan to go into detail on the physical experiments on the piano, such as taking it apart, replacing parts etc…