Can anyone could help me remember the name of a "journey to mars"-type movie. All I remember is that you see the groups of guys (about 3) chill behind some rocks and they see a group of these short green alien humanoid-shaped beings. There's a trough of water and the aliens are drinking from it. But the one at the end is slightly weak-looking, so then the group attacks it and feasts. Then either this pile of rocks starts to build itself into a organism thing and attacks them, or it attacks the human guys. But it was at least 3 times taller than them and made out of rocks.
I know these if very vague but I've tried and can not find what this is, so if any of you have a clue THANK YOU.