Complex sentence: He was discovered by, and became apart of the "Enterprise's" crew, buried part-way in sand, apparently the sole survivor of an attack by the Crytalline Entity on an off-world.
Split into simpler sentences: He was discovered by, and became apart of the "Enterprise's" crew, buried part-way in sand. Apparently the sole survivor of an attack by the Crytalline Entity on an off-world.