It doesn't feel pity, or remorse, or fear. And it absolutely will not stop, ever, until you are dead
...or captured. Or you give back that MacGuffin
You're being pursued by someone or something. Defeating it is out of the question, any encounter will be a Hopeless Boss Fight
. Any "successful" fight just involves delaying it temporarily so you can run away some more.
Before I flesh it out more, Do We Have This One?
- The Songbird from BioShock Infinite. It appears you don't fight it so much as inconvenience it so you can keep running.
- The first two Terminator movies mainly involve Sarah Connor running the hell away from the Killer Robot.