A recent question asked for a natural mechanism for a creature to escape one planet and go to another. The answers prompted me to this question. Given any answer to this, is there any plausible case for evolution to enable a creature to leave a planets biosphere and go to another, not by begin blasted from the surface by a meteorite or titanic volcanic explosion, or genetic engineering. I suppose in other words; is naturally evolved [panspermia][1]. possible? My guess is no, but cannot help but think there may be perhaps some cyclic devastating conditions that eventually leads to this possibility. "Life finds a way." I would prefer the creature be multicellular. But would accept answers for spores or seeds type transmission. EDIT: To make things even easier, we can assume a minimal gravity to sustain a life bearing atmosphere. [1]:https://en.wikipedia.org/wiki/Panspermia