All this wanting to be like Bowser is something the coin takes literally.

The coin didn't take Peach's thoughts of being like Bowser unnoticed, in fact it took them quite literally. It glowed brightly between her scaly breasts and began to change her once more. Peach's hair became shorter, and more wild, as her reptilian face lost any amount of femininity it had once possessed. Her entire body got larger, thicker, more powerful, with a rotund stature that made it clear she wasn't someone watching her weight. Her breasts themselves ebbed away into the solid wall of chest she'd claimed, and her genitals were the last thing to change as she suddenly stood there looking at the coin falling to the ground with nothing to support it, her clothes completely shredded, a complete physical copy of Bowser.

Looking at the gold coin, Peach realized it was what had done all of this to here: Become What You Seek. She'd wanted to be strong enough to escape, then to be more like her captor, and both had come true. "Grahahaha!" Peach roared, laughing loudly. "This is perfect! Now I'm the epitome of bad! The most powerful man in the world! No one will ever kidnap me again. In fact...I might start **** people! Bwahahahahahaha!" Peach had no problem with the change in gender, with any of this. She was too engrossed in the arrogance, in the power, to care.