This postcard cannot possibly be intended for cat lovers. Would you sit a small kitten between two lighted candles? No, the red velvet background gives the game away - this is obviously some sort of satanic rite.
I'm not sure if the kitten is a sacrifice, or whether she is actually an evil minion of the dark lord. Look at those eyes. A Hypno-Kitten maybe?
To add to the overpowering effect, this is an extra-large postcard (6" x 8"). On the other side it says 'If more than conventional 5 word greeting, Letter Rate applies.'
I'm just guessing, but I suspect the conventional 5 word greeting is "All Hail, Your Satanic Majesty!".