what or who was scylla
This Monster is based upon the Ancient Greek sea monster Scylla. Scylla was a six-headed monster with tentacle-like legs who's heads rapidly snatched and devoured the crew of any ship that passed nearby. Nearby was the monster Charybdis and sailors passing through the area had to choose between facing (and surviving) either of the two, ergo the idiom Between Scylla and Charybdis.