The dude should shit the banana onto a canvas and then sell it for $500,000... he can call the piece, "Artistic Bullshit".
Clearly some people have more money than sense. Why anyone would pay 120g for a banana an strip of duct tape that cost less than a buck stuck to the wall is beyond me. Any 5 year old could produce that "Art" if you gave them a stool to stand on to get it that high up the wall.
Sure your paying for the "Certificate of Authenticity". It certifies the holder as an authentic moron.