"Well I would say to be able to swim underwater like you, but I don't want to lose my legs."
"That's not a problem" replies the mermaid "I can make you a frog-boy instead. You will need to remove your pants, shoes and socks though."
You agree to this, and strip to your shorts below the waist. "This won't be permenent, will it?" you ask.
"I will turn you back when you are ready." answers the mermaid.
Having stripped, the mermaid starts to transform you. Your skin turns green, your legs grow longer, your feet extend into large flippers, your hands become webbed and you lose your nose and ears, now replaced with holes.