This gallery has a selection of monsters and hybrid humans adapted into deep sea creatures. I found this image of a girl opening a treasure chest from which many strange creatures are flying out of really interesting.
Click the numbers below to see some of the stranger works from the site.
1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9
Artist found thanks to Armchair Aquarium