Is it normal that i have a ghost in my wardrobe

My cat is scared of my wardobe. Some nights he'll sit and stare at it, walk backwards and growl. I also have strange happenings around the apartment. Yesterday my cat sat in the hallway and stared into nothing while listening. I have started having things disappear and reappear. My cats toy was lying in the middle of the kitchen when I left it together with my cat and sat in the living room with my cat next to me the whole time with a movie. When I walked back the toy was gone I looked everywhere, under every furniture with a flashlight and even in drawers. Then after a few hours it was in my bedroom on the floor INFRONT of my wardrobe.. Also a key that keeps going missing. It always sits next by the front door but twice it has been gone randomly, one of those time I had just used it literally 5 minutes earlier to be in the basement which requires the key to use the elevator to get down there and I needed to go back down again as I needed to check something else so I walk back to the hallway again and the key is not where I had just put it. Started looking everywhere very confused and then back to the hallway again and the key was back but instead of where I had left it, it was chucked behind a bunch of other things like somebody had lifted those things to put the key behind them and then put the things back again in an attempt to hide it... And now it is my cat being scared of things no one else hears or sees and who is never scared of anything. Tonight after I had gone to bed I heard three knockings on my wardrobe on top of everything else...Very odd. Like someone in there... But of course theres nothing there. Dont ya think ive looked?
What would ya'll do?