Riddle - Oil Spill

Dark and foreboding, I float upon a wave; the life I touch most often dies. Some from the poison in each kiss I gave; my burning fumes can blind their eyes. Others I seek out with viscous tendrils; suffocate, smother, I steal their breath, Pour sticky darkness into their gills; wash them ashore on a sea of death. On Pelicans, otters and seals I prey; hold them tight in my tarry embrace, On nearby beaches by the thousands they lay; shivering, wretched in their dying place. If you light me on fire, toxic smoke fills the sky; now let me ask you, what am I?