The mask transforms him into a female Gerudo.

As the mask touched Link's face, he felt it immediately jump and cling on to him, the mask beginning to sear with raw magical energy. Link screamed, terrified of what was happening, but before he knew it the pain was gone, as was the mask. Instead, Link looked down to see that he now had the body of a Gerudo warrior, with the only difference being that his clothes were green instead of purple. The feeling of his large breasts being contained in a green top that was more of a brassiere than a shirt was both embarrassing and slightly arousing. Link turned to face the Happy Mask Salesman, who was suddenly there again, and asked what exactly all this was.

To Link's irritation, the Mask Salesman had the same expression as before, his mouth stretched in a toothy smile and his eyes seemingly closed. "I told you these masks possessed great magical power, did I not?"

The Hero of Time was **** to admit that was true, and that the mask would help him enter the Gerudo Fortress. But how could he turn back.

The Mask Salesman let out a high pitched laugh at that. "Oh, it is very simple. Just take off that mask, like you would any other. It is still there, you know, even if you can't see or feel it." The Mask Salesman turned around and started to walk away. "I hope you enjoy my gift, young hero. Goodbye..." And with that, the salesman vanished midstep, as if he was never there in the first place. Now, Link realized he needed to think about his next step.