Earl Grey, black, with a slice of lemon: amazing!
Y'see, I'm not a fan of milky tea, and I only ever have half a teaspoon of sugar in mine.
Oh dearie, dearie me Thufir. You're being haunted by something and it'll come in the night.
It'll come in the dark as you slumber fitfully, tossing and turning as your primal sense scream to your unconscious mind; screaming the warnings of millennia as the thing which breathes on the other side of the reflection crawls out from the erupting shadows and stumbles in towards your bedroom.
Sluggishly, you'll awake from your eerie half - sleep as your primitive terrors force you into uncomfortable waking where you know only that it is coming, but you know not what it is.
You creep your way over to the bedroom door and see that the bathroom lights were left on by another housemate and you go to turn them off, only to see out of the corner of your eye a lithe and unwholesome thing slip with its preternatural grace out of another room and float towards you. You, who simly stand there, frozen in the full realisation of it.
You will never escape it.
It will take you.
It will take you back behind the reflections into the world where it will play with you, eat you, tease you and eventually end you.
You will never be again.
Umm, cats are Discworld elves. Remember what Magrat says.