what is this?

what is this?

A friend sent this from her property. It was on a trail. Only one. She thought animal print but it's raised up. I was thinking that something is growing under the mud? Very strange. Not an April fool joke :)

Okay, first of all it looks like an unintended optical illusion - I look at it one way and it is raised up. I look at it another way and it looks indented/depressed.
If it really is raised, then I have no idea what it is.
If it really is depressed, there are no claw marks and that makes it a cat.