A team of scientists have revived a bacteria after a hundred thousand years under three kilometers of glacier. The microorganism is one of a new type only recently revealed to science, is small enough to pass through standard sterile filters..
These super-small cells are extremely suitable for life on otherwise untenable planets, with their minuscule food requirements, extreme resilience, and adaptability to micro-niches which couldn't support even regular sized bacteria. As well as existing where others couldn't, these sublilliputian lifeforms could persist on planets where catastrophes wiped out everything else.
The new ultramicrobacterium (and that's not hyperbolistic neology, that's the actual scientific name) Herminiimonas Glaciei was recovered from underneath Greenland glaciers and took almost a year to slowly heat back to life.