What did Scylla look like? Homer gives her six heads armed with triple rows of teeth on her shoulders. Ovid gives her six dog’s heads at her waist and twelve dog’s legs. Neither of them mention the long mermaidy fish-tail that she’s usually depicted with in art (where she’s a sort of mermaid with a dog or two grafted to her waist).
So which is right? One or all of them? Rodney Matthews’ excellent illustration from The Usborne Book of Greek and Norse Legends (1987) bravely tries to include as much as possible.
All in a very alien sort of look. No twelve legs though.