About 200 million years ago, a leech released a slimy mucous cocoon that unwittingly encased and trapped a bizarre animal with a springy tail, preserving it until researchers discovered the teardrop-shaped creature in Antarctica recently.

The cocoon looks like those produced by living leeches, such as the medicinal leech Hirudo medicinalis. Encased inside was a bell animal that looked similar to species in the genus Vorticella; its body extends 25 microns (about the width of some human hairs) with a tightly coiled stalk about twice that long. And like all eurkaryotes, the organism was equipped with a nucleus -- in this case, a large horseshoe-shaped nucleus inside the main body. (A micron is one-millionth of a meter.)
read more: http://news.discovery.com/animals/bizarre-creature-found-in-200-million-year-old-cocoon-121208.html