You take a deep breath somehow (yes you have lungs and are amphibious) And gain full control of your body.
Your 8 limbs feel everything about your new Body. Then You find the zipper in fact you orient one of your eyes to See the zipper. You focus and unzip.
Darkness.
You decide to probe a tentacle in and pull out a hairless 5 inch flaccid human adult cock. It feels warm and solid as a wave of pleasure hits you. You see it grow errect to 9 inches and the foreskin starts to peel back revealing a hyper sensitive cock head.
You squirm as you decide the floor of a costume shop. You make your way to the changing rooms.
In the changing rooms you start to tug at the errect and quite inconvenient penis. You wrap 2 then 3 then 6 tentacles and start contracting and squirming causing a moan to escape from you somewhere. To think of it You don't have a voice bOx to create sound.
After a while you cum. As you do you black out for a moment (due to the pleasure) when you wake up you find a adult male human costumed attached to where the zipper was.