I made my serpent costume using a bald cap, latex prosthetic face pieces, horns, gills and ears all hand painted with grease makeup, decorative gauze, rubber fins and feet. I also have mesh sleeves and floppy fin spikes made out of mesh material down my arms.
I also have a tail filled with beans. It took about 10 hours to prep and paint and about 3 hours to apply. It also took about an hour to remove.