I woke up and noticed a huge handprint on the top left side of my bathroom mirro!

Years before I was born someone wrote in shoe polish on the mirror in my childhood home. Years after it had worn you could see traces of it when steam fogged the mirror. Probably cleaning it brought out some sort of residue that was on the mirror from years ago. or if you have recently moved into the residence the former occupants could still have keys
change the locks
look through the house good, someone could be living in the basement

ooh, that's freaky. if you have security cameras around your apartment then you could look at them to see if anyone has left or entered the building that night. you could also see if it happens again, if it does then it might be a ghost (but that's very unlikely). If it was someone in your apartment then i doubt they would return. Has anything been stolen? if you're very worried about it then get security cameras actually in your apartment. if this shows nothing, but you are still getting hand prints, then contact a paranormal activity specialist to come check out the place. but never rule out the posiblilty that it could be your hand or a friends hand that came to stay.

your house or apartment is probably haunted, the more you fear it the more it will reveal its self, ignore everything it does as if it were just some odd action, dont let it get to you and make sure your doors are locked!!! dont watch any scary movies and dont leave yourself open to situations to where your going to be in a dark room watching a movie or tv show keeps your lights on so that you can have a sense of security and if you dont have an animal get one again so you feel safe.....you can always just move or have someone move with you. dont try taunting it again just ignore everything odd that you see or hear if your sure there isnt a creep in your house.

did you do a chick against the morror and she had soapy hands? if so .... there i go ... soap stops mirros from fogging = ghostly hand print = freaked out guy = hahahaha

wait until you come out of the shower and someone wrote BOO on it, then worry... you could be in a swayze movie

Call a priest, get religious

nothings is missing.....but i found this lava lamp

Omg.. Call a friend to come over then search your house everywhere.