What Are These?S

These objects seems to vary from shapeless blob to chaotic scribble—but they are in fact short-lived structures that have been captured in fine 3D detail for the first time. Can you work out what they are?

Sadly for you, we're going to let you puzzle over the answer for a little while. To give you a helping hand, the images were captured by researchers at the University of Utah, who used a pretty cool setup of three high-speed cameras triggered by infrared sensors to shoot the objects every 1/25000 of a second.

We'll post the solution here in an hour or so. Until then, try and work out exactly what it is amongst yourselves in the comments-without cheating and resorting to Google Images.

Update: Here's the answer.