You're a bit nervous about what the people at the front desk will think of you, but surely species reassignment is business as usual by now, right? You've heard of dozens of people doing it even in your neighborhood, even though some of the neighbors had some nasty things to say about their choice. You never told anyone you secretly envied those people.
The valedictorian of your high school turned decided he'd had enough of everyone's constant expectations of him to be successful and decided he'd be better off as a sea creature swimming free in the ocean. Your 79-year-old next-door neighbor finally retired from the local transit service and decided he deserved a break after 50 years of putting up with assholes late for their commutes five days a week. He wanted to spend his last years with constant companionship and not a care in the world. He turned himself into a terrier and sleeps in a pet bed in a fellow retiree's apartment. One of your ex-girlfriends who had always wanted to live on a farm decided the easiest way to make her dream come true was to become an animal for the farm. For a while, you wondered if you were the one who inadvertantly disillusioned her with human life and pushed her over the edge to become a farm animal of some sort, but you eventually decided you shouldn't blame yourself for something that wasn't a bad thing anyway. She's probably having the time of her life on a farm somewhere without any of the pressures of owning it, and you can easily fulfill your dream of living as an animal, as well.
You ask about the possibility of becoming an African animal, and the receptionist tells you that there are many options of African animals to become. Especially if the species is endangered, you are likely to be placed into a breeding program to replenish the population. It's entirely possible you will be placed in an exhibit; species reassignment is a popular option for keeping zoos in business while letting originally wild animals stay free in the wild. It's also possible that you will be directly released into the African wilderness, so you do need to consider the possibility that you will end up as prey or a predator. You would never be given any real choice in the matter, but you do have the option to choose now which species you will become.
You fill out the form to tell them what species you want to be and other information as well, and you are led into a room and ask to take off your clothes. You look down at your penis and balls one more time and realize that they will not be human genitalia much longer. Your parents' fantasies of you giving them grandchildren are over, but the possibility of spawning new wildlife into the African ecosystem is very real. Not even bothering to care about your human modesty or societal expectations to restrain your urges now that you've agreed to be an animal, you go ahead and give your manhood one last hurrah while the doctor is reading your paperwork and waiting for the nurse to bring the serum. It feels the same as it has since puberty, a final bastion of normalcy before you ditch your familiar existence once and for all. Your neighbors will say you've thrown away your life the way your girlfriend did, but what do they know? They'll have to put on clothes tomorrow and keep running the status symbol rat race they spend even more time complaining about than species reassignment.
You accidentally kick the table and moan as you pass the point of no return, not even caring that you caught the doctor's attention just in time for him to see your last human load squirt out on the floor. You see the disgusted look on his face out of the corner of your eye, but you know what? Fuck him. You'll be getting one little injection, and then you'll be out of his and everyone else's life forever, and they'll be out of yours. You'll eat what you can find, drink what you can slurp up, piss where you stand, fuck when you can find a mate, and jack yourself the fuck off whenever you want, if animals are able to do that. The nurse walks in just as your sticky penis goes limp, she and the doctor talk about you like you aren't there, and then the stick a needle in your belly button, which sucks. Then they shove you out into an outdoor enclosure, and you see them picking up a mop before the door closes all the way. You can already feel something starting to happen.