Greg kneeled down, struggling against his new, unfamiliar weight.
"Whoah, there's all sorts of animals in here..." Greg breathed.
"Yeah, there are," Mark said absently. He glossed over the animal vials and paid more attention to the human ones.
"What is that? A rat?" Greg asked. Mark glanced over.
"Uh, yeah," he concurred. "Ah, here we go!" He found a long line of what looked like attributes. One had a figure with exaggerated muscles. Another had a weirdly serrated outline, like the teeth of a saw. A third vial had two figures: one small, and the second big. Right next to it, on the fourth vial, the bigger figure was on the left and the smaller on the right.
"That one looks like it might make me smaller," Greg suggested.
"I dunno, I think that it would make someone shorter, not thinner. What about that one?" Mark gestured towards another, with two figures, both seemingly identical.
"Worth a shot, I guess..." Greg murmured. He pulled it from the rack and drank it. He replaced it, and the vial refilled. A moment passed, but nothing seemed to happen. Mark took a look at it. The figures looked the same. It was hard to tell what it was meant to portray. Next to it were similar vials. One with a man and a woman, and a third with two women. They weren't the gender vials, though. The Male Vial was blue and had a picture of a single man. Further down the line were pictures of a figure with a halo above their head and another with cartoon devil horns. Good and evil? Was this series of mental transformations?
Greg made a strangled noise of shock. Mark turned to look at him. Greg was staring at Mark's ass. Still completely naked from his first transformation, Greg was unable to hide his erection. His face was bright red. Mark looked back the the vial. Sexuality vials, perhaps? The one next to it had a man and a woman on it. It was probably the Heterosexuality Vial. He deftly turned it around so its label was hidden. Maybe he'd give it to Greg later. Maybe. Not straight away, at least.