(a) "Defiance" alien (by 2015?) by Tristan Jones
b) Cover art for Clive Barker's Books of Blood vol 1 (Published 1988).
I should point out that I think this piece of artwork references 'Fall of the Damned' (1450 approx) by Dieric Bouts, which is the other thing that I think the alien beast drawing references.
I don't know who should have informed Mr Jones that there ought to be a connection, or even if he consciously thought that there was one at all, but once I connected the cover with the Bouts painting, I have a confused realisation about how it might also connect with the alien beast drawing and weeks later it would seem clearer,
c) Here the black clouds in the distance become the general form of the cranium of the alien beast
d) Clive Barker's face becomes transformed into a detail on the groin. That's a bit weird, but well.
e) Upper arm of the humanoid lends itself to the form of the leg
d) The face of a horned demon lends itself to the ribcage area
e) The hand becomes the teeth, a man's eye becomes an eye like form in the neck with the hair line become the edge of the fin on the right.
The ears or horns of a demon that curve downwards to the left lends itself to the shape of the fin on the left of the alien beast's face