I've been wanting Aunt Marge fic forever, and I was thrilled to see this story pop up. Only in Beholder. I've been saving the reading as a reward for finishing my school year, and it's lived up to all my hopes for it.
I love the "strong woman" motif, the "eyes that see through lies," and the way you join the two subplots at the end. Marge and Dolores are perfectly-suited to each other (love the connection you draw between dog breeding and pureblood breeding). Myrtle/Millicent is lovely, too; I love inventive uses of magic, and your ghost-sex is inspired (as are the details of ghost clothes, etc). It's great that you're able to preserve the unpleasant sides of each character at the same time that you make them appealing (in their own ways); they have all the complexity of real people. And Ripper -- omg. From the minute he stared at Dolores's shins, I knew he'd be a triumph. (And the way you introduce his humping is hilarious -- no need for any description.)
The Snape scene is another grand touch; his voice is spot-on. All the cameos, in fact, work so well: Percy and Stan and the others.
Other lines I adored:
for some reason she did not want to insult the British palate in front of this woman.
Until such time as you return to normal you might find it advantageous to be seated for certain necessary functions. Hahaha
in the manner of all small couches when inhabited by large people, the furniture had conspired to shift them close together
The humor of this piece is just so perfectly suited to the characters, and there are sufficient touches of seriousness to anchor everything quite well.