The Padlock Key is a key item in Gregory Horror Show: Soul Collector. It opens the door to Room 102, Neko Zombie's cell, so you can talk with him or give him food.
How to obtain[]
On Night 1, after Neko Zombie asks you to retrieve the key, go talk to Gregory at the front desk. He will leave to begin his rounds shortly afterwards. Once he leaves the lobby, get the key from behind the desk.