What if we are the aliens on this planet? No, seriously. The most popularly believed theory of human evolution is that a bunch of apes migrated from Africa across the world and then evolved. Now, I say alien invasion could have been equally possible.
Circa [whatever the year was about 5 Mn years ago]
M1: Yo Bro, let's go.
M2: Wa'ssup Jesop.
M1: Did you hear about the blue thing last night?
[A nuclear bomb blasts some 50 miles away shattering glasses and spewing smoke and ash. A deafening sound later]
M2: Say, what?
M1: The Blue Thing dude. Looked cool. You got to see that?
M2: Oh nope. I was collecting leaves for winter. These leaves are itchy. And besides, it's fall time so time for some colorful ones, Everyl likes the colors.
M1: C'mon man. They had projected the damn thing on to the big screen last night. That thing looked beautiful.
M2: Where is it anyway?
M1: I don't know, must be some 100 Mn miles away.
M2: And, you wanna go there?
M1: Hell yeah.
M2: Alright, let me ask Everyl.
E: Adambach dear, why do we have to go?
M2/ A: Everyl babes, it's cool out there. And besides, I frankly don't like the fall colors.
E: Hmm... ok. Let's go.
M1: [Suspicious] Man, that was easy. Are you sure she has no other plans? These creatures from Venus, I tell you. They have made Mars a living hell man.
[A bomb explodes]
E: Say what?
M2/ A: Nothing dear. Appleton was just praising you.
E: Of course. Too bad I couldn't get my DM61A1 with me.
E: Damn this place is cold. I told you we should have got some more leaves for covering ourselves. Oh, there. That looks like a garden. Lets collect some leaves. Wish it were fall season here.
M1/ Ap: Oh Everyl, shut up will you.
M2/ A: Eve dear... he is just kidding.
E: Adam, eat him.
M2/ A: Err... but...he is the only one who knows...this is a sin... I mean, all the knowledge..
E: Adam... eat that Apple, now.
And the rest, as they say is mythology.
Come to think of it, we are the most intelligible species on earth. We are almost the 'newest'. And, for all we know we must have dumped some desolate little planet for a better place to survive and made this our own. The resident species, dinosaurs, lions, dogs an crows were dumb, technologically illiterate and used power to rule. They must have had sightings of many such space ships landing with alien humans being spotted now and then. And before they knew it - we came, we saw and we conquered. I don't think the dinosaurs went through a natural extinction process. Them damn things were just taking too much space.
Am I watching too many Sci-Fi movies?