Pool, pool on the ground, who's the fairest one around? We are? Yes, we are…
The pool (or mirror) is one of those awesome, timeless symbols that's been everywhere and done everything. In its purest form the mirror is a symbol of truth. No matter how we lie to ourselves, our reflection is always true. This is why vampires don't have reflections and evil Disney characters are always trying to break their mirrors.
Over time this symbol has split into two versions. The first version relies on characters who like (or want) what they see in the mirror. This is clearly where Narcissus fits in. Narcissus is straight-up obsessed with his reflection. So obsessed he's willing to chill out by the pool until he starves to death.
In this version of the symbol, the mirror represents a danger. Think about the Mirror of Erised from Harry Potter and the Sorcerer's Stone, which shows onlookers whatever they want most in life. But as Dumbledore explains, many people have withered away and died while staring into the mirror. Sound like anyone we know?
The second version of the symbol relies on characters that hate or despise what they see in the mirror. This is where the vampires and evil Disney villains fit in. In this instance the mirror represents a truth that the character can't face. For vampires, it proves that they're dead. For Disney villains it usually proves that they're ugly. Or at least that they're not "the fairest of them all." Boo-hoo. Dorian Gray, from Oscar Wilde's The Picture of Dorian Gray, goes so far as to stab his self-portrait because it reflects the truth about him as a person. Yikes.