Identification help please

[soul4surfin]

I started noticing these "clump-like" patches on my sand bed. One area was close to glass and it looks to have started growing on my glass. I dug just underneath another clump/layer in another area of my tank and found a few critters which I do not know what they are.

So two things I need identified

1. Critter (image 1 and image 2)
2. Clump/like layer (that is purplish on my glass)

Thanks in advance as everyone has always been helpful with identification.