Luke used to hate looking in mirrors. His mother had always told him that the way he looked was nothing to be ashamed of, that his long ears and bushy hair, his warts and protruding nose were to be expected in a healthy goblin, were admirable. He had dismissed her wisdom, like usual, not caring until too late, and gone back to fretting over his reflection. He had been a vain creature, vanity so strong and not usually found in creatures deemed "ugly" by the rest of Halloweentown. All he had wanted was to be handsome, to look like a mortal.
One day, his wish had been granted. A dark thing with an aversion to sunlight had offered him good looks, and respect of certain hard-to-impress Halloweentown circles, if he would agree to be his operative in the daylight hours, and Luke, blinded by the desire to be beautiful, the greed for easy respect, had agreed in heartbeat.
When Kalabar had been vanquished, the spell had been broken, and he had reverted to his normal form. He had cowered inside Marnie's red cloak, breathing in her scent as he cringed on the cobblestones, praying she would forget about him, hoping fervently that she would leave without the cloak, that she would not see him this way. She had come for the cloak, though, and to thank him for his help, and he was encouraged by the fact that he did not repulse her. She was not even disturbed.
When he got home, his mother didn't say a thing about his new (old) appearance, but she smiled behind the newspaper, and gave him a hug. He looked in the mirror that he had arranged to be prominently displayed in his room, and saw all of his warts and his long ears, his yellowy skin and his bushy, tangled rust-red hair. But he wasn't disgusted, the way he thought he would be. He had grown up considerably, thanks to Marnie. He knew that his looks weren't something he should have to hide or shy away from. He was a goblin, and now he knew better than to want to look like a mortal. He was proud of the way he looked. And would never be so stupid, so blind as to help something obviously evil again, let himself be pulled under by the promise of something easy.
But, as he removed his mirror from the wall, tucked it under a dropcloth in the attic, the fact that he had realized his goblin looks weren't something to wish away, that didn't mean he wanted to be reminded that he no longer had any sort of chance with a certain Cromwell witch.
