You don't notice anything, but as you sleep you begin to change.
Your ears sharpen and grow quite a bit. They then move to the top of your head and grow black and tan fur. Your eyes turn amber and your pupils become slits. Your nose turns pink and becomes animalistic as it pushes out into a snout, dragging your mouth along with it. Whiskers push out of your cheeks and your head reshapes into that of a lynx's. You sprout tan and white fur all over your head, and parts of it begin to recolor into black spots. The fur spreads down your torso and creeps down your arms and legs until it covers you completely. As more black spots form, your hands grow paw pads on your palms and your fingernails sharpen into retractable claws. Your fingers shorten and your thumb moves up to your arm forming a dew claw. Your hand then takes the shape of a lynx's paw and your feet go through the same transformation as your hands, causing your shoes to slide off. Your tailbone extends a bit, forming a nub. You begin to shrink until, at last, you are the size of a lynx, practically suffocating you in your own clothes. Now THIS wakes you up. You struggle for air and you surface just in time for your bones to shift. You fall off the chair onto the floor as your legs shorten to the same length as your arms. The joint in your knee reverses, causing you to fall to all four. Your spine shifts and your neck now stands at the stature of a four-legged animal. Your bones pop, signaling the end of your transformation.
After a moment of thinking about how this happened, you remember how you licked your lips and you scream. The reason why Pure Lynx Extract is heated before served and never given to patrons is because it's not reversible.
You're stuck as a lynx forever.