The Fake Beanstar looks pretty similar to the real Beanstar excepts it looks a little faded.
The Fake Beanstar was mainly used to try and fool Bowletta. After Mario and Luigi retrieved all four pieces of Beanstar, Bowletta shows up on a hologram and demands the Mario Bros. to bring Beanstar to Joke's End for a trade for Princess Peach. Queen Bean, knowing that Bowletta will just make off with both Peach and the real Beanstar, then comes up with an idea to try and fool Bowletta with a crafted version of Beanstar and sends Mario and Luigi down there to do the trade. However, Fawful isn't fooled as he quickly sees that it's a fake and still takes Princess Peach away. The Fake Beanstar isn't seen again after Fawful blasts it away.