Voldemort still wasn't sure whether it was actually safe to kill Potter, so he'd Transfigured him into a donkey. As far as he was concerned this had been a total success. After overcoming his initial tendency to kick him and bray at him, Potter had settled down docilely onto his pile of straw in the corner of Voldemort's chambers, and was now very little trouble.
The donkey poo had made the room rather smelly at first, but Pettigrew had helpfully provided a spell that Vanished faeces as soon as it hit the floor. Voldemort was happy, but Bellatrix had become rather suspicious as to how Pettigrew had been so familiar with this spell, and a brief enquiry had turned up the news that his chamber contained a hundred and twenty-six rats. The Death Eater headquarters were plunged into temporary chaos as every room was fumigated; Nagini hid in Harry's pile of straw and hissed irritably when approached.
"Milord," said a perturbed Amycus Carrow, "'Ow come this donkey can hiss?"
Harry munched placidly on his carrots and ignored the disturbance.
A few of the Death Eaters proved mildly problematic, but it was nothing Voldemort couldn't handle. Lucius Malfoy lingered near the donkey in a very suspicious manner and had to be shooed away, and Snape's first appearance was most unfortunate, as Harry bared his teeth horribly for a moment and bit Snape on the backside. Voldemort, however, found this most amusing, so Snape wasn't allowed to poison his carrots.
In short, everything went smoothly until Ali Bashir arrived.
Voldemort wouldn't normally have allowed himself to be exploited by that sort of vile old spiv, but he had no option: he was short of a number of vital goods that couldn't be obtained from the British magical community, and Bashir was eager to provide them in exchange for a way into the UK market. Also, Voldemort had to confess that he was rather curious about those flying carpets. Looked a lot comfier than a broom.
There is no way of knowing how the exchange would have gone, or who would have won the war, had Voldemort not invited Ali to meet him in his chambers. Ali was ushered into the room, began "Assalam alai-" and then stopped dead as he noticed Harry.
Voldemort grinned. "Hello, Mr Bashir," he said. "Don't mind Mr Potter there. He's been rendered quite harmless." This was not strictly true, but witch hazel had worked wonders for Snape's nether end.
Ali said slowly, "You have Transfigured Harry Potter into a donkey?"
"Yes," the Dark Lord said, nettled (not literally, as Harry had eaten them). "Is there anything wrong with that?"
"It's not a very auspicious choice, Mr. Voldemort," Ali said vaguely, fixing his eyes on an invisible object six inches to Voldemort's left. "Allah turns men into donkeys for arrogance, and you are certainly not Allah."
Voldemort promptly thought several blasphemous things about Allah, but kept his temper and purred, "I do apologise. Donkeys don't have the same symbolism here. Did you have a good journey?"
Ali carried on contemplating the wall and said, "Actually, I believe they do have some symbolism to Christians. Marium and the Prophet Isa had a tendency to ride on donkeys, which is supposed to be why they have crosses on their backs..."
"All right, I just don't care about symbolism," snapped Voldemort, realising that he had not seen his temper for several minutes. "And he doesn't have a cross on his back, he has that stupid lightning bolt. Shall we get on with the discussion?"
At that moment Harry raised his upper lip at Voldemort as if he had smelt something revolting, and gave an excessively loud hee-haw.
His temper now long since in the Left Luggage department, Voldemort shouted, "Shut up!"
"...And also," Ali concluded, "donkeys bray when they see Shaitan."
The business discussions did not go at all well. Ali Bashir had perfectly plausible reasons for not supplying Voldemort with the goods he needed, and he was a competent Occlumens; but the Dark Lord suspected very strongly that Bashir had turned against him, and it was all Potter's fault. Typical bloody Potter, even as a donkey he was a pain in the arse. Voldemort decided that he would make up for it by torturing and killing those Granger and Weasley girls. And the werewolf. And the Longbottom boy as well. All the same, by the time Ali Bashir said "Goodbye, Mr Voldemort," he was still in a very bad mood.
"It's Lord Voldemort," he shouted after the door had closed. "Can't you at least call me Voldemort-Sahib or something?" He was vaguely aware that he was thinking of the wrong country, but after all, he reasoned, India and the Middle East were pretty much the same. "And that's all rubbish about you being dangerous," he told Potter. "Isn't it? Isn't it, Neddy? Bloody Muslims, what do they know? All pagans and foreigners."
After all, Harry didn't look dangerous. He was just a little grey donkey with long eyelashes and black-tipped ears and a black lightning-bolt mark on his back. Upon being asked this question he flipped an ear at Voldemort and munched his thistles sweetly.
All the same, Voldemort had nagging doubts. "Oh, well," he grumbled, "I can transfigure you into a mouse or a gerbil or something, if he's that bothered about it," and he raised his wand.
The spell backfired and Transfigured Voldemort into a gerbil. As Nagini began to circle, a hungry look in her eyes, Voldemort had a few precious seconds in which to contemplate the importance of religious tolerance.