Hi Levelwind,
yes, it could be, like this:
From sol 1357, it looks like a sphere. ^_^
Wow nice finds Noone, sure looks mechanical to me. I like the entrance for? thread too.
I see what you mean about the tank, looks like hoses coming out of the left of it
and maybe an eyelet on the right or what was the top.
I also thought this thing looked artificial as well. It's just to the right.
Happy new year!
Here two "rocks": a probable axe and a strange object with two little cylindrical tanks.
http://mars.jpl.nasa.gov/msl-raw-images/msss/01375/mcam/1375MR0067360050701719E01_DXXX.jpg