Screaming volcano
This seriously disturbing image is not actually a photo, and it's not actually an astronomical object! It's an image of the Eyjafjallajökull volcano in Iceland when it was erupting in 2010, made using radar observations. 

But c'mon, look at it! How could I not include it?

Image credit: Icelandic Coastal Patrol

Original blog post: Blowin' off some scream