You open the large package, discovering nestled among layers and layers of newspaper is a single amber beer bottle. You pick the bottle up and examine it. "Wolf Spit" is written on the label in brilliant green and yellow striped, vintage looking, lettering. You never heard of this stuff, but free beer is free beer. Without a second thought you pop the top and start drinking.
You feel it slide down your throat, it's awful, it feels warm, slimy and thick. You gag on your drink and try to spit it out. Much to your dismay though you can't get it out of your mouth, it's actually expanding, slobbering out the side of your mouth onto your blue carpeted floor. You start feeling strange, a tingling sensation engulfs your body. Without warning, you buckle over in pain as you start to grow taller and your bones restructure themselves, your expanding form rips your clothes, leaving them in ribbons on the floor. Massive sharp claws start growing on your fingers and toes. Thick fur blankets your newly nude body, You're teeth sharpen into fangs. You feel everything else slide into place bit by bit from the transformation. Soon it ends and you rush to a mirror finding it easiest to run on all fours. Staring back at you is a drooling, snarling werewolf, completely unrecognizable from the human you were before.