A grin was on the face of the monster
Careful attention to detail here renders Victor's account
dubious. With all lights extinguished so that the room is only
illuminated by the moon, it would appear next to impossible for
Victor so sharply to distinguish a visage that would be backlit
in such circumstances. Neither the Creature's own narration in
the second volume nor his account of his struggles with Victor
Frankenstein at the end accords with such a perspective of
fiendish exultation in evil. This portrait is, however, wholly
commensurate with Victor's increasing tendency to demonize the
Creature. See 1.6.9, 2.2.4, and 3.3.1.