The Moon: The muse immediately gains weight, situated around their rear and spreading up to their waist and down to their calves.
Maka was sat on her couch, using her free time to catch up on her reading, when she suddenly felt a tingling in her rear. Confused, she reached a an arm behind to scratch at what she figured was a random itch, but otherwise didn't think much of it as she grew engrossed in her book. Until that is...
cccrrrrrrrreeeeeeeeaaaaaakkkk
ccccccCCCRRRAAAAAASSSHHHHHHH!!!!
The living room couch collapsed, sending a jolt through Maka's body as her blubbery form was deposited abruptly on the floor below. Groaning, the scythe-meister tried to stand up and inspect the damage, only to find... she couldn't. Even more confused, Maka finally turned to look over her shoulder, causing her eyes to go wide.
She was used to being fat. Having a huge rear, flabby thighs, a stomach that brushed the floor, all of that was normal. What wasn't normal was seeing her doughy rear reaching higher up than her own head did, almost reaching the ceiling of the room. Nor were thighs and cankles so pumped with blubber that her feet had practically been subsumed, as Maka found as her gaze shifted downwards.
Her eye twitched. There was (she assumed) only one explanation for this.
"BLAIR! ARE YOU MESSING AROUND WITH MAGIC AGAIN?!"