He sat back, and gazed absently at the other side of the wall.
He stopped smiling.
Then, eventually, he spoke.
"I've just realised why you all usually slept," Albus Dumbledore – the painting of Albus Dumbledore – said to his fellow former heads. "This is boring."
"We did try to explain," Phineus Nigellus said, sarcastically. "Several dozen times. You might try going for a walk."
"I've been everywhere on this castle," Dumbledore replied. "Seen everything. I tell you, it's dull."
"No kidding," Armando Dippet sighed.
Dumbledore sat silently for a moment.
"Bobble," he said after a moment. "Cafaddle."
"What are you doing?" Phineus said.
"Foa koa daggle doggle dingle bomb," Dumbledore replied. "Fa kaddle po po hatter batter."
"You're insane," Phineus said. Dippet and a few others were sniggering. "What are you doing that for?!"
"Random noises with my mouth," Dumbledore smiled. "Dingle dongle hatilian boop. Boop oop a doop. Fee fi fo fum hiddle piddle sniddle…"
Half an hour later, when Severus Snape walked in, Dumbledore was still at it.
"What are you doing?" he asked the painting.
"Faddle snip," Dumbledore said, before smiling at Severus. "Hello Severus, I'm just relieving my boredom."
"Well, if you could stop," Snape said, "I have work to do…"
He sat down, and Dumbledore obligingly fell silent.
Then, as Snape started marking some papers, he heard noises.
"Bingle bongle dingle dangle, yickedy do, yickedy da, ping pong, lippy tappy too ta…"
Snape spun around ,and Dumbledore grinned.
"If you weren't already dead," he told the portrait now grinning like a lunatic, "I would kill you. You know that, right?"
Some time afterwards, Ginny Weasley stood in front of the Headmaster.
"Miss Weasley," Snape said shortly, "while it might be difficult for you to comprehend…"
And then, to his annoyance;
"Day doo de bop. Day doo de bop. Day doo de bop. Day doo de bop…"
Music had just started, absurdly, from nowhere – annoying, repetitive, and Snape spun to face a singing Dumbledore.
"I am trying to maintain a Death Eater look here," he grumbled, ignoring Ginny's sniggering.
"#There's a monkey in the jungle, watching a vapour trail," Dumbledore said, ignoring him. "Caught up in the conflict between his brain and his tail…"
"Miss Weasley, if you want to spend a whole term in solid Detention," Snape sad, spinning to face her, "you will keep laughing."
She kept laughing.
"#And if time's elimination then we got nothing to lose. Please repeat the message – it's the music that we choose…" Dumbledore continued. He grinned as the music kept blaring out. Just at that moment, Alecto Carrow entered.
"Snape I…" she stopped. "What's that?"
"The portraits have a sense of humour," Snape said dryly. "Leave, I'll deal with whatever it is later."
Ginny Weasley laughed out loud as soon as Carrow left. Snape sighed.
"Why am I surrounded by mental patients?" Snape wondered. "Miss Weasley, leave, and don't come back here. At least - not until he's calmed down."
Dumbledore kept singing. Ginny, laughing, left. Snape turned on him.
"You just want me murdered in my bed, don't you?" he said.
Dumbledore kept singing.
"I've had enough trouble for a lifetime," Harry said, and he and his friends left.
"Right," Dumbledore said, and he smiled. At that point, a small cough came, and he turned to see Snape smiling from a different portrait.
"If you thought death was hell," he said, "you just bloody wait."
And then, loud, raucous music started.
"#I can't decide, whether you should live or die…"
"Burn me," he said to no one in particular, as Snape kept singing.