I've been rereading a wonderful fanfiction of Tsubasa Reservoir Chronicle, called The Missing Worlds. In one scene, a group of underwater serpents guard a magical glowing feather. I felt inspired to try to draw it.
I went based on this description: "They were serpents, or something like it; as they got closer Syaoran could make out undulating, smooth bodies with hides that reflected the light like an oil slick. Their mouths were full of needle-sharp teeth and their eyes glowed a smoky red, smoldering coals of rage and hate that strained against the water."
(The Missing Worlds, Chapter 4: Water World III)
