Other mistake: As the priest walks out of the haunted mansion with his head twisted, you can see the head and body don't step in time together.
Other mistake: When Kat chooses her bedroom in the mansion the bed should be covered in dust but it's not.
Answer: It was not Casper (now a ghost of 12 yr old boy) who wrote there was a hidden treasure at Whipstaff Manor. It was Casper's father, Mr. Mcfadden. The treasure in the box is an autographed baseball which used to belong to Casper, before he got sick and died. Mr. McFadden missed his young son Casper, so he invented a machine that can bring a ghost back to life. He considered Casper's baseball a treasure, because to him it is the greatest treasure there is - the baseball that belonged to his 12 yr old son before he died.
Super Grover ★