The dizziness from the serum has barely worn off when your backbone tenses uncomfortably. You straighten, you hunch, you even twist a bit, trying anything to relieve the strange feeling! It feels like the vertebrae themselves are changing, shifting, moving to new places, and even multiplying. When the uneasy sensations have passed, there is still an unfamiliar wobble just over your butt, as though something were hanging where your tailbone used to be. Widening your eyes at the realization, you snap your head around and find your ropy tail. It isn't furry yet, but it does have a shaggy tuft of long hair at the very end. A sudden impulse makes you move it, and you see it swing to the left and flop back down to dangle where it was. You grab the tail and wince, pulling it around in front of you to examine it better.
"Come on, surely it can't be that shocking, can it? You already knew--"
"Shut up!" you interrupt the condescending police officer while you hold your long tail gently. It sinks in that it's truly yours until you die, and that dying is really going to be mean getting butchered into steaks or ground up into burgers. You have what any bovine has at the end of its spine. A bizarre stretching feeling elsewhere makes you groan and hold your new tail against you like a security blanket. You realize the stretching is in your feet, so you lift them up and look at them to see what they're becoming. Your feet have stretched so far that you wonder how you're going to walk on them, when you see your toes sprouting sturdier nails that soon reveal themselves to be cloven hooves.
"How could I have been so stupid?! Stealing from that old bitch just to end up like this? I was just a normal bloke, and now, and now--"
"--and now you're about to be a lot more impressive in the downstairs department!" the officer cuts into your self-pity monologue just to mock your crotch. Of course, it doesn't look all that impressive at first. It looks like you're becoming a female! Your dick gets sucked right into you and disappears under the skin of your abdomen. After that, though, you feel your penis swell inside you, getting longer and harder, snaking upward inside your belly, before a hairy opening forms right in the middle. You touch the hairs and shiver, feeling a newfound sensitivity right at the very tip of your bull-like sheath. Your balls swell and your scrotum sags until you can't believe the size of your new genitalia! The hormones that surge through you cause an erection, which sticks out like a pink rod from inside your long sheath. It throbs and makes you want to touch it, but it looks disgusting--it's an animal's equipment for fucking cows, rather than the manly organ of pleasure you've taken for granted.
Then the fur grows in! Black strands seeping out of your skin wherever they can find a spot, covering your legs and tail in no time and spreading up your bovine sheath. It doesn't stop, either, more dark hairs appearing everywhere you had bare skin. It just keeps spreading and spreading, and then...