There was a crash, as Tonks knocked over the troll-leg umbrella stand. Everyone braced themselves for the screeches of "MUDBLOODS, FILTH, HOW DARE YOU BESMIRCH THE HOUSE OF MY FATHERS," but instead they heard ... silence.
Sirius came jogging down the stairs. "What's going on? What happened to ..." He pulled aside the curtains over the portrait of the deceased Mrs. Black. She was keeping suspiciously quiet.
There was nobody in the portrait frame. Sirius tapped the canvas. "Mother? You missed your cue."
"Go away!" squeaked a voice. It did not sound like Mrs. Black at all.
Sirius gave the portrait a shake. "You need to come out and do your annoying shouting bit now. Get a move on, we haven't got all day."
Mrs. Black's head slowly peeked into view from one side of the picture. Somebody had drawn a mustache on her face.
Sirius dropped the curtain and turned to the others. "All right, which one of you smart arses did this to Mum?"
Mrs. Weasley blushed slightly. Tonks exchanged looks with Ginny. Hermione shrugged. And Mad-Eye Moody just smirked, which looked very odd on a face like his.
"Right, where's that bottle of Mrs. Skower's Magical Mess Remover ... Kreacher, get over here and clean this up, will you!"