Final answer:
The symbol is intended to ward off vampires, creatures from ancient myths known for drinking human blood.
Step-by-step explanation:
The symbol in the image provided is intended to ward off vampires, according to the lecture. Vampires are a common supernatural hazard features in myths from many cultures and are traditionally known to drink human blood for sustenance.
Tales like Bram Stoker's Dracula and television shows such as Buffy the Vampire Slayer have popularized the concept of vampires, which originate from ancient folklore and supernatural beliefs.