I am trying to find a movie that I watched when I was young, its a alien movie?

Hi, I am trying to find this movie when I saw when I was small and right now I am 16 so it can't be that old, but its about these little martians they come in these little spaceships and its kind of a comedy and they attack the whole world, they get the president, I think they suck their brains idk really on that but it was a awesome movie and it had a couple trying to escape them, one scene I rememeber is that they were by a cave and hiding from them and it wasn't a cartoon it was like real life with critters (aliens) attacking and destroying the earth, plz can anyone give me a list or any thing you guys think it would be and also they have their little outfits.