Open crater on Mars, gateway to Martian hell?

Maybe it is the entrance to Martian hell like in the computer game doom3.

Or maybe and very unlikely its just a natural rock formation made by erosion or asteroid strike?
What say you?

I'm pretty sure it's not natural.

If anyone has a giant plug, please step forward.

call the space marines from doom3.
They will fight the demons.
They have the BFG in their arsenal.

Not The first ! -> [link to apod.nasa.gov]

photoshopped image by NASA.

<waiting for Astromut shill to butt in>

Can we not believe what NASA has to say?

Intersection of shallow crater with subsurface lava tube?

If not, how about a chemical/mineralogy effect with the impact pressure leading to (e.g.) a metastable, high density ice that that was then more prone to sublimation?

If we knew what the rock was, that might help. Either way, though, I wish they'd send a probe down there... I'd love it to be something more... unexpected.