For me it looks like Mars'ish or kinda Desert'ish... In both cases, "Flying Saucers" is an option (on Mars or in the Desert, Area 51, hehe) ;-). On the ground you could have threelegged Spiders, which also fits to 50/60s Horror/SciFi Films and would be a nice reference to "It came from the Desert". Also, if it's on Earth/Desert, big wolves or camels, packet with rocketlaunchers or railguns, would fit. Or, if it's on Mars, why not green littl' men, with laserguns? ;-D