...try on the black t-shirt with the red hourglass printed on the back. You stare at it, you have one idea of what it might do to do but you wont really know till you try it on.
You go back to your bathroom to get a good look at what could change. Gulping loudly you rush the t-shirt over your head, you must find out what these shirts do before someone else stumbles on them by mistake. As you completely put on the t-shirt a whoosh of sensations hit and a momentary dizziness hits as if you were drunk. As your head clears a bit the first thing that is immediately apparent is your vision, you can see in more directions but somehow they still blend subconsciously to make one image. In the mirror you can see you're clearly still female but also strangely still bipedal, you've become some black widow hybrid thing. Your face has three sets of smaller eyes, all pitch black; your mouth is almost normal but has two mandibles like a spider sticking out from the sides with two more protrusion which you assume are poisonous fangs. As things sink in you start to feel your extra set of limbs, three sets of thinner arms with three digits on each.
"Luckily you've kept your opposable thumb" you think.
Another thought hits, how are you walking? Your stance is off but you feel like your standing just fine as if by instinct. Looking down you see are standing on your front 'toes' which are similar to your hands but only two digits and thicker allowing you to stand. You also notice your butt is huge and has the hour glass symbol on it now instead of the t-shirt, you guess there are spinnerets inside that huge rump now. But come to think of it you still have the shirt on and you see it's changed to comminate your extra set of limbs with extra sleeves. Since you were into fantasy and a little into the idea of furries this look was turning you on.
But you had other t-shirts to try and college to go to, you cannot stay this way forever. "Maybe this would be a good Halloween outfit" you think. You ponder what to do next as you check out more of your new self. You decide to...