Dishonored: Death of the Outsider

Throughout the game, you'll find tons of rats. I'm not gonna point out a specific location because there's just so many of them around, it really shouldn't take more than five minutes to find a swarm at any given time.

1. Find some rats you can interact with

2. You can literally just interact with any rat five times. Doesn't have to be unique, don't need to save scum.

3. Cheevo popped.