the creature was hit three times.
the arm, the abdomen and the upper chest, the one in the chest being the cause of death. it shattered, for want of a better term, the creature's backbone. it's not really, because it's not jointed. it's simply a hollow shaft of very pliable silicate material, as is its entire endoskeleton. the creature seems to have tremendous regenerative powers. although it must have died within minutes of receiving the fatal wound, the arm and abdomen wounds are almost totally healed and the bullet here.  has begun to dissolve.
it has veins but no blood. we think, and this is just speculation, that some form of energy flows from the brain, which is much more sophisticated than ours, throughout the rest of the body.  we don't think there is any danger of bacterial contamination. our biochemistries are too different.
the flesh is gelatinous, the skin is very porous and very moist. this is another guess, but it probably comes from a planet that receives only reflected light, perhaps from a ring of moons. its atmospheric pressure is slightly less than ours and it contains a great deal more water.
they're so advanced.  i.  eh.  can't imagine what they would want from us. i know they could be dangerous. but they could also be the greatest thing that ever happened to mankind.