How about cellular automata simulating (spoiler) complex life forms in many dimensions, implemented in large polysaccharide constructions? :) (Greg Egan's "Wang's Carpets", later incorporated as a chapter into his "Diaspora".) http://bookre.org/reader?file=222997&pg=1 (http://archive.is/ocAgN)

I always found that to be a little sad. iirc, the Carpets in the story are completely deterministic - while there is life there, it will always unambiguously lack free will. (Though I suppose they'll never know it.)

That was the Horta in the original series. It finally said "No kill I" after Spock mind melded with it.

"The Devil in the Dark" Season 1 Episode 25