tlhingan maH!

...Klingon.
Karyn suddenly felt an extreme headache, worse than any she had ever known. But it was not merely a headache; her skull was rippling and distorting, being thrust up and down like a tectonic plate, until shaping itself itself into a pattern of gently cresting ridges upon her forehead. Her skin darkened by a shade, and her hair, although remaining blonde (as per her earlier wish) became long and very thick. Her mouth became full of sharp fangs, and her clothes rearranged themselves into a barbaric sort of armour, complete with shoulder pads, black fur sleeves and metal gauntlets, and a shirt which opened, exposing her cleavage. A vicious-looking dk'tagh dagger now hung from her belt, and her sense of smell suddenly improved a thousand fold.
She gazed defiantly at Jon, who now stood a full foot taller than he had been, and now sported forehead ridges of his own, as well as a Fu Manchu mustache and Klingon armour. Karen snarled with delight, and Jon emitted a low growl upon seeing her. She leapt across the room and tackled him, just about to bite him on the cheek (and thereby initiate the Klingon mating ritual) when she stopped.
"We can't do this!" she exclaimed. She was shocked to note that she was actually speaking in Klingon, not English.
"No," intoned Jon. "I suppose not. It would be dishonourable. We will, afterall, revert to being Humans after a day, and we would regret it then."
Karyn nodded in agreement, and climbed to her feet.
Jon looked around and curled his lips in disgust. "This is a weakling's bedroom!" he declared. Siezing the stone in his gauntleted fist he barked: "I wish I had the room of a true warrior!"
Both Klingons had to look away for a split second, but when they looked up, they saw that the room was now decorated with Klingon swords and icons of Kahless. Jon's soft, cushy bed had been replaced by a solid iron slab.
Jon nodded his head in approval. "Come!" he said. "Let us see if we can get anything to eat!"