The Engine

This comic makes use of the artwork Blockmaker engine from Glitch, a former multiplayer online computer game that released all its artworks into the public domain.

Title: "The Engine".

A cartoon scene: two aliens, one blue and one purple, both are basically blobs with one big eye and some tentacles, sit on a grassy backyard lawn, in the background is a house wall with a door. Between the two aliens is a thing that looks like it might be a car engine or a lawnmower engine, with several cords of insulated wire dangling from it. Alien 1: Whoa... is that what I think it is? Alien 2: A real, working, internal combustion engine. Amazing, right? Alien 1: Can I touch it?

Alien 1 (gingerly touching the engine with its tentacles): I've seen them in museums before, but I've never seen one so well-preserved. Look, it's covered in sticky black stuff! Wait, is this stuff poisonous? Alien 2: Only to humans, don't worry.
Close-up of Alien 1 holding the engine in its tentacles: Just imagine! Countless eons past, life appeared on this planet. Then some of the creatures died, and after millions of years their corpses were converted to fuel...

Another close-up of Alien 1 holding the engine: And millions of years after that sentient beings evolved on that planet. They dug up the fuel and, tragically, created an entire industrial civilization that depended on it, even though it was obvious the fuel would one day run out!

The two aliens both peer closely at the engine. Alien 1: So they built these machines... From what I've read, there should be a combustion chamber with cylinders. Which part is the cylinders? Alien 2: I dunno, it's kind of all welded together.

Alien 1: Just thinking about those poor, doomed, long-ago beings gives me chills! Alien 2: But it wasn't long-ago for the humans, for them it's happening right now! They don't know that other alien societies have already been through this.

The door in the background is partly opened and a little girl looks out, but the two aliens haven't noticed her. Alien 1: That must be weird for them. Alien 2: Haha, yeah. Alien 1: D'you think we should tell them how it ends? Alien 2: Nah.

The door to the house has been pushed wide open. A cute little girl with her hair done in Afro-puffs stands in the doorway. Girl: Um, guys? Do you know what happened to the car? Coz my Mom is REALLY mad right now. (Both aliens look at the girl guiltily).