Even worse: Alpha dog.
Imagine this: You decide to go for a quick run in the forest not far from your home. It's late December, it hasn't snowed. The sun is setting but you are confident you will make it out of the forest again before it gets completely dark. As you go you meet no other runners, nobody is walking their dog and it is getting colder and darker with every step you take. You should return, but you have almost reached half of your usual round. So you go on, thinking of the hot shower that will reward your effort and ignoring the growing emptiness around you.

When the music in your ears falls silent before a new song comes on, you can hear the quiet rustling of the dead leaves beneath your feet and the rhythm of your breath echoing in the stillness of the dark trees around you. And then you hear it. You fumble for the pause button in your pocket and you slow down, not sure if the sound is just the base drum of a new song beginning. Or maybe, just maybe, you have only imagined it. You pluck the headphones from your ears. But you can still hear it, somewhere in the dark. And it is getting louder. A mechanical thumping, fast and unrelenting. You stand still, look around. The forest is a maze of black tree trunks in an ocean of dark blue nothing. The path before you is dimly lit by a violet ravine that cuts through the branches high above you. And still the thumping gets louder. Not only louder, but closer.

You start to run, faster this time. It's only a few more minutes to where the path leaves the forest and merges with a paved road that will lead you home. For a few seconds you can't hear anything apart from your own heartbeat and gasping, but then - continuous and measured - the thumping, now a mechanical thunder, breaks through. You can feel the ground vibrate beneath your feet as you try not to lose the way in the dark. Home is just a few steps away. There finally is the lighter opening, the end of the forest, only about 100 feet before you.
And then you see it.

At first it's just a huge shadow, moving slowly and steadily until it stands still, right in front of the oval opening in the trees that is your salvation. You see little green, red and white lights flicker as it remains immobile, like a statue. It's edges are sharp, it's posture like that of an animal, yet there is no head, no breathing, no soul and no eyes. It is a thing, a gigantic black thing on four stumps. And you cannot move as with a mechanical shiver it starts to turn in your direction. Run, you think. It's too big, to clumsy, it can never get you, if you just run! But your legs do not obey, as it's hydraulics start hissing in the silence. With a sudden roar the machine throws itself into movement. The ground shakes as it's legs beat down on it faster and faster. And it is coming at you.