R.L. Stine 
Nightmare Room #12: Visitors 

You hold in your hand the key to a shadow world of shivers and screams. Take a step away from the safe, comfortable world you know. Unlock the door to terror. There’s always room for one more in . . . The Nightmare Room.Every night Ben Shipley searches the sky for beings from outer space.But Ben doesn’t know there’s a real live alien much closer than he thinks!