[you can be any animal you want and you can even change the story if you want]

you had been adopted by a nice human they took you home and let you explore but you had come to realize you weren't the only animal in the home and you were right but you never saw the other animal but always felt watched.

one day your owner had left for a business trip and wouldn't be back for a few months you had time to explore more of the home but as you explored you felt something off you saw a room that it always locked now open you look into the room to see a giant monster if it were to see you, you would surly not survive.