What is it?

[indominus rex]

I have asked about this before but I had bad quality pictures, I found it in the Rosheim forest which has recently been known for its mammoth bones that were found. I decided to go there for a look and this one caught my attention and I first thought it was a fossil coral because the mountain was once submerged under water. Please help me find the identity of what it really is.

[TqB]

This looks like a sponge, with a spicule network.