It adds 55 new cards to mix into the base deck, adding to the stick-figure, serial killer mayhem. New cards include, "Aneurysm", "Election Tampering", "Self-Defense Classes", "Gary Coleman", "Plague Rats", "Sledgehammer", "Trunk of a Stolen Car", and more.
From the publisher's website (used with permission):
"Live fast, die young, make a PRETTY CORPSE"
Sporks and weed whackers just not enough for to slake your blood lust anymore? Looking for a little more madness in your mayhem? Just mix the 55 cards from A Pretty Corpse into your Let’s Kill deck and add even more distinctive stick figure art and gruesome humor to your next game... because the great thing about dead bodies is that you can make your own.