There are a whole bunch of creepypastas about things like the first mission to Mars finding a human skeleton in an old Soviet space suit and something written on a rock nearby.

Stuff like: "We are not allowed to leave... they will be coming..."

Or waking something up <_<

R'lyeh is in the south Pacific, go back to sleep sir.

...under "a few" to 20 kilometers of ice even.

* Richard Greenberg suggests "a few" kilometers. * Robert Pappalardo suggests ~20 kilometers.