Yesterday, while my cousin and I were hiking in the German alps, we stumbled upon some very bizarre creatures in a small permanent puddle in a cow pasture at around 1500m above sea level. What we at first saw was what looked like a colony of tiny red things undulating together and anchored to the silty bottom of the puddle.
After poking the moving red mat, it quickly receded and disappeared under the surface leaving little holes.
Here's what the red things turned out to be - little red worms.
After taking pictures and doing some online research at home, we determined that they must have been Tubifex worms. Here are the links to the German and English Wikipedia pages.