You wonder if you can make a smaller change than splicing your DNA with a totally different species, and start looking through a section with human presets. They're much more subtle and simple- this one changes your muscle mass, this one changes your hair colour, this one your eye colour, this one your age, et cetera. After some consideration, you decide to try one of the more dramatic ones in this section- sex. Hypothetically, this one would change you from male to female, which sounds pretty out there without being as weird as mixing up your DNA with another creature.
Hiding yourself behind the trash can so no one will see you transform, you select this preset- and instantly feel a weird shiver run through your body. Your skin feels tingly and itchy against your clothes, and you pull your shirt off to relieve it. This gives you a great view of your skin convulsing and its texture changing- all of a sudden it's smoother, suppler, more petite.
The intense sensations move up your shoulders and neck, and you squeeze your eyes shut for a few seconds. Using your phone to see your reflection, you see a young woman- she still looks like you, just with a few hormonal and chromosomal changes.
You get a vivid reminder of your emerging womanhood as your chest grows sensitive. Your nipples swell and flesh forms around them, giving you large pert breasts. Hastily you pull your shirt back on to cover them as best as you can, only for the sensations to flow downwards to your hips and crotch.
Pulling your jeans and boxers off, you peer past your larger chest and unwittingly watch as you lose your penis. Your phallus recedes into your body, the head forming a tiny sensitive nub. You also feel your testicles get tugged up inside your body and reshaped into ovaries, while your scrotum splits to form a vagina.
Once the changes finish, you're stunned at your transformation, and hastily pull your jeans and underwear back up, wondering whether to turn back...