"But a lot of teenagers metabolism change when they hit puberty and again when they hit their twenties," Stiles stated with a shrug like it all made sense to him and that what Michael did really wasn't a horrible thing. "And have you tried a constant intake of something really bad for you? See if that puts on weight?"
Then the attention turned back to his potion and with a grin Stiles pushed down the pants he was wearing to show off his bright blue thigh. He of course still had boxers on. "Hasn't faded in colour nor was the potion blue when I applied it. It didn't spread and the spot is still tender which means the bruise was healed. I have no clue what I did wrong."
After Michael got a look Stiles pulled his pants up and nodded. "Definitely. Muggleborn. So you plan on taking an inanimate object and turning it animated with a potion?"