Aliens trolling us

Ok... but what else could it actually be?

Aliens trolling us

Bigfoot.

Earthquake. Oops, crap, no, um ... Mars-quake.

I guess, but I would hope that would've been detectable.

It also would be quite remarkable since Mars is tectonically inactive at current state of knowledge.

"Earth" is seriously a bad name for our planet.

"Rover did it somehow", even at a remove or two, isn't exactly an unsatisfactory explanation....

Calvin and Hobbes?

Honestly its not like we have many real options. The rover flipped it or it fell there sound good too me. The area is pretty open there so it didn't crack off another rock, let alone the shape precludes that.

Photoshop

Could be the work of 4chan? Is the transmission encrypted?

This will the first letter O in a series of anomolies spelling O-P-O-R-T-U-N-I-T-Y-R-O-C-K-S (sic)