Features: Upper half of a beautiful woman, bottom half a serpent
Source: Greek Mythology
Echidna was an extremely beautiful woman from the waist up but her bottom half consisted of the large creepy coils of a snake.
She would entice men with her tantalizing attractiveness, all the while concealing her lower half so she could lure them into the darkness to kill and devour them.
Even though she is recognized for her great evil, she is most remembered for the destructive children that she gave birth to.
This stunningly attractive beast joined with her colossal husband Typhon to attack Olympus. Their siblings also joined in this battle, but Zeus kept them all at bay by throwing bolts of lightening at them.
Many gods really wanted this powerful seductress killed, so they conspired and sent the 100 eyed giant, Argus Panoptes to murder her.
While also filled with the absolute fear of this formidable creature, he committed the crime when she was deep asleep.