Yes. The symbol, we can agree, is intended to be a serpent.

You see, in her final hour, Lydia Martin wished to divulge the truth and, with her dying breath, cast a curse, a most vicious curse, upon the villain who slew her.

And so she draw a serpent, to indicate a snake in the grass, a viper among us. And so shall our villain be, a terrible viper indeed. We must look for the one whose dreams are haunted by Lydia Martin's ghost, come in the form of scales and venom.