Ominous

It lurks only in the dyling light.
Sprinting through the shadows prying fright.
You can barely hear it, it's out of sight.
Silouhettes of a demonic figure when the thunder flashes light.
It's gone in the blink of an eye, so be careful when you bat your lash.
In and out as quick as flash and it can weild a knife just as fast.
Don't be surprised when you're throat is gashed.
You thought you had it once it sprung, so you swung.
And it stuck its hand threw your chest and detached a lung.
As it starts a backwards countdown from 10, it
laughs as you die before it reaches 1.