5. Chucky (Child's Play)
There isn't much scarier than a creepy-looking doll. That is until said doll comes alive and starts killing people with a really big knife. Chucky was previously Charles Lee Ray; a murderer who, whilst dying, transferred his soul in to a Chucky 'Good Guy' doll using a voodoo spell in order to keep himself alive. He then continued where he left off in his life as a human - as a cold-blooded killer. As a Sinestro Corps member, Chucky could escalate his brutal, devious, crafty murderous ways up to a cosmic level, becoming a galactic-serial killer. I would imagine his constructs would mostly be knives - multiple knives - and that he would take great satisfaction from roaming the galaxy killing anything that got in his way.