Internet forums are full of chatter about the picture, taken by a panoramic NASA camera known as Spirit.
One alien-spotter speculated: "The skull is 15 cm with binocular eyes 5 cm apart. The cranial capacity is approximately 1400 cc.
"There appears to be a narrow pointed small mouth, so this creature most likely is a carnivore."
Another joked: "The coronal ridge shows ample structure to support the musculature of antennae, although none are visible in this view.
Joke now, but it's all fun and games until you wake up with an antennae in your you-know-what. And by 'you-know-what' I mean your girlfriend -- she's gonna cheat on you with an alien. Hey, don't cry, film it.
'Alien skull' spotted on Mars [telegraph]
Thanks to Chuck Nunchuck and Julian, whose relationships with Martian lovers have all ended the same: with them getting the shaft. The cold, metal shaft.