Answer:
The more of it there is, the less you see.
You use a knife to slice my head. And weep beside me when I am dead.
Steals an event or even a mood. Reveals the truth or shatters it.
Looks like water, but it's heat. Sits on sand, lays on concrete. A play on the eyes, but it's all lies.
A kind of weather that comes your way, but add a "D" and it will run away
Long and slinky like a trout, never sings till it's guts come out.