Popular to common belief, Donnie was a very intelligent boy. O.K. maybe not the intelligence most people think of, but he was smart enough to figure out what he could. He knew how to put on clothes, even though he didn't. He couldn't concentrate long enough to only speak one language though he understood most of what was being said to him. He lacked the care to try and figure out how to respond. He'd realized that the one called Eliza could talk to animals, he knew he was stronger than the monkey, he recognized the screeching from the one called Debbie was his name, and how best to scare an animal on the off chance he wasn't stronger than it. He had also figured out what he liked; what bugs tasted the best and which berries gave him indigestion. Yes, Donnie was smart.
Donnie also got confused, he was only human. But unlike most humans, his brain worked at such a speed that he processed what was and was not working in order to simplify the situation. Donnie did not understand things like 'tact' and 'social protocol' it was why he handled things the way he did, and he was often right to rush in even if he was confused. When he'd first seen the boy, he'd found him interesting, and assumed it was the clothes. So he'd followed him. When the boy had taken his clothes off to wash them he ran to them and (after toying with the boy a bit) took off with them. He put on the clothes trying to be as interesting as he'd found the boy. When that didn't work, he'd tracked the boy's sent, finding the ones that had his smell on him. He lived the boy's life for a while, before deciding that it wasn't for him, nor was it what made the boy so infuriatingly interesting. As his attention span shorted out, he forgot about it until he saw the boy again.
"Hey! Gimmie back my clothes, I don't like bein half nakie!" Donnie took a good long look at the boy…as much as he could look with the glasses ruining his vision. The boy has crazy red hair, it's what had grabbed Donnie's attention in the first place, it was only now that he realized exactly how well it suited him. It was a fire against snow white skin. And he had little…things across his face. He wanted to press at them, but the look on the boy's face, though adorable, was usually followed by yelling and other shows of 'anger'. He got what he wanted; he knew why the boy was interesting. He gave him a roguish smile and obeyed the command.
_
He kept the shoes. They were a bit nicer to his feet and it was troublesome to switch them…at least, that was the excuse he'd give if anyone bothered to ask. The truth was that he never wore them, he also never returned them. They were in the back of his space, along with the shorts the boy had worn. He sniffed at them until the smell was gone. Even then, he kept the shoes to stare at. They weren't quite the right color, but they did their job; remind him of the boy. Their parents even stayed in contact with each other.
When Eliza went to college, she brought Donnie and Darwin with her. Darwin because she didn't know what she'd do without him, Donnie to try and civilize him a bit, as it seemed he had gotten worse rather than better (and that he talked animal more than English and so she was the only one that could understand him). They were currently living in the Lipchitz's guest house. Donnie was currently still being homeschooled, nothing could make him wear a shirt and shoes for extended periods of time, and the school wasn't budging on the rule. Eliza had assumed that he was being shy, so she'd arranged a slumber party for him.
It had ended two minute after it began. A red-headed boy came and Donnie went crazy, babbling and switching languages faster than Eliza could hope to keep up with. He grabbed the old shoes that he'd stolen once upon a time. Eliza had apologized as they left for her brother's behavior.
The next day, he woke her up by jumping on her, and it was only by clearing her eyes and grabbing her glasses did she notice, Donnie had stolen both Darwin's shirt and a pair of her shoes. His babbling was gibberish at the moment, but he was franticly signing 'school'. She blinked a few times, before deciding that since the boy changed his mind often enough, she'd better get him registered. Eliza got dressed lightning fast and soon; Donnie was enrolled in the 8th grade.