Are Ghosts Biblical?

The question is often asked, "are ghosts Biblical?"  It is a sad truth that many Christians spend very little, if any time reading/studying the Bible and are unaware that the Bible mentions ghosts several times. Jesus Himself was thought to be a ghost by His own disciples who did not recognize Him when He was walking on the water toward them (Matthew 14:22-26; Mark 6:45-52). Because the average Christian spends so little, if any time in the Bible, when they are told by their minister or Sunday school teacher that ghosts are actually demons impersonating the dead, they accept it without giving it any thought and are astonished to find out that ghosts are mentioned in the Bible when it is shown to them. I also note that not once did Jesus ever say that ghosts are demons and He certainly had plenty of opportunity to do so. At Luke 24:36-43, Jesus was regarded as a ghost by His followers and He had to partake of material food and be touched to convince them that He wasn't. It seems to me that if ghosts do not exist, Jesus would have taken this opportunity to say so, but He did not. Instead, what did He say?
"And he said unto them, Why are ye troubled? and why do thoughts arise in your hearts? Behold my hands and my feet, that it is I myself: handle me, and see; for a spirit hath not flesh and bones, as ye see me have" (Luke 24:38-39).
Instead of debunking the existence of ghosts, Jesus actually confirmed their existence with the above statement in my opinion. So, yes, ghosts ARE Biblical!