It's the -xane cone, like msgiblet said, which is really's called cyclopentasiloxane. I'm not sure if all the -xane cones are bad or not, but I know for sure this particular one is.

Cyclomethicone is actually a rather mild cone, from my experience. I think using coco betaine or CO washing can get it out. Everyone's hair is different. I would assume you will need more than just a water wash as it isn't technically water soluble...but mild washing from CO washing or from non-sulfate shampoo should be enough.
That's right, I said it! I wear scrunchies!!

I am a sulfate washing, cone slabbing, curly lovin' s.o.b. The CG police haven't caught me yet.