There is little danger and no violence in Little Kitty, Big City, so it may come as a shock when players look at the achievements list and see one called Killer Kitty.
How to Complete Killer Kitty | Hidden Achievement ► Little Kitty, Big City
To complete the Killer Kitty cat feat, you'll need to find a "dangerous item" and chase down a human pedestrian with it in Little Kitty, Big City. Fortunately—or unfortunately, depending on the type of gamer you are—you can't hurt anyone with a dangerous item, but you can force them to flee in a different direction.
You'll find a short sword in the southwestern part of the map, in a trash can in the closed off area next to a ramp leading to a garage door and the yellow soccer goal.
Jump onto the bed of the red truck to the right of the ramp, then jump up onto the ledge using the boxes. Follow the ledge all the way around and drop down into the closed off area, then dive into the trash can. After searching the trash can, you should get a couple of Shinies and a short sword. You can pick up the sword (near the blade with your teeth, alarmingly) and use the nearby boxes to get out of the closed off area. Then all you need to do is run towards a human NPC until they show an alarmed exclamation mark and run away.
