snake dragons aren't original at all, so please make whatever snake dragon you'd like to!

in order to be a serptail, it would need to 1) be based off a real snake and 2) be one of the 3 serptail "types" (colubrid type has double-plated bellies, round pupils, forward-pointing horns, 2 horns on each cheek, 2 sets of upper teeth, and 2 nostrils. venomous type has single-plated bellies, slit pupils, backward-pointing horns, 3 horns on each cheek, long fangs, 2 nostrils and 2 heat pits, venom sacks on each cheek, and sometimes spines along their necks. python types have triple-plated bellies, slit pupils, backward-pointing horns, 3 horns on each cheek, :3 shaped mouths, 2 nostrils and at least 6 heat pits.) as long as your snake dragon doesn't copy those traits exactly, then there's no issue whatsoever :) have fun