(From Solar Tadpoles)

For several years, scientists who study the sun have been intrigued by this mysterious phenomenon. Dr Valery Nakariakov and Dr Erwin Verwichte analysed observations obtained with NASA's "Transition Region And Coronal Explorer" (TRACE) space mission. They theorize that the wiggles of the tadpoles' tails are earth-sized waves similar to the waves in a flag blown by the wind. They think that the waves are produced by a phenomenon known as "negative energy waves"; waves pull energy from the medium they propagate through. The "tadpoles" are optical illusions, rather than real physical structures; the apparently descending tadpole head marks the falling start point of the matter's upward acceleration.

(From Solar Tadpoles)

Science fiction writers have long had fun with the idea that living creatures could exist in the intense heat of a star like our sun. Arthur C. Clarke wrote a wonderful story about a solar observatory on the planet Mercury that made an incredible, unexpected observation during a massive flare:

We were looking at what seemed to be a translucent oval, its interior laced with a network of almost invisible lines. Where the lines crossed there appeared to be tiny, pulsing nodes of light...

What we were seeing was impossible, yet the evidence was there before our eyes. We were looking at life, where no life could exist.

The eruption had hurled the thing out of its normal environment, deep down in the flaming atmosphere of the sun...
(From Out of the Sun ~1959)

More recently, Stephen Baxter wrote in his 1994 novel Ring about photino birds, creatures that lived within suns, and could even fly between them:

She descended into the Sun, through the ... flock of photino birds. The birds soared past and around her, tiny planets of dark matter racing through their tight solar orbits.

The birds continually nudged toward or away from each other, like a horde of satellites maneuvering for docking. Many of the transient clusters they formed ... seemed immensely complex. There had to be a reason for all this activity...
(From Ring, published 1994)

It turns out that there was a reason - but you'll have to read the book to find out! Other works in the "creatures on the sun" genre include Proof by Hal Clement and Sundiver by David Brin.

Read the original article at Solar Tadpoles Wave At Astrophysicists; they also have a very cool solar tadpole animation that demonstrates the uncanny movement that gave birth to the name "tadpoles." Thanks to Fred Kiesche at the eternal golden braid for the tip and some sf background on this story.