Well you have done fantastic so far!  The planets are with you!  This will be the last you will have to find and then you're off.  Peeves has gotten bored with tormenting the students and teachers of Hogwarts, so he decided to try us out here in the Forbidden Forest.  He'll get it from the Bloody Baron if you can catch him.  The nasty little Poltergiest has been throwing everything he can get his hands on.  And he keeps on sneaking up behind me and pulling my tail!  So I hope you catch him quickly my young friend.  Good luck once again.