Sans was having a bad time. The thing, he couldn't read its face clearly. But the smoothness and accuracy it slipped past all his blows with indicated it had some sort of foreknowledge. He wasn't sure if he was furious or terrified. It didn't matter. He knew he couldn't dodge forever, and he already felt himself tiring. Putting his bony palms up, he pleaded. The angel was bouncing between its feet, as if preparing itself. It wasn't listening. Sans wasn't surprised, then, when the blade came swishing through the air for him; he got out of the way. He tried to be intimidating, but it just wasn't him. His special attack, right. He'd use that. He warned it, but it merely tightened its grip on its knife. Not one to lie, he tried his Not-So-Special-But-Still-Very-Effective move. While it was able to keep itself alive, he took satisfaction in its struggle, in every wound it took. He was panting. Defeated, he used his Special Attack. Of course, that was what he did best; nothing. It looked confused, angry, and maybe even a little scared. It could just reset, sure, but it'd just get back here again and again.
Now, Sans didn't mean to fall asleep, but the struggle had worn him out. So he took a quick little nap, that was all. He wasn't dumb or anything, and certainly not a deep sleeper. He heard the whoosh of the knife and stepped out of the way, once again. Shrugging, he started to scold it, but it was faster than he expected. It had its knife to his shoulder.
"Why couldn't the skeleton beat the child?"
Its voice sent shivers down his spine.
"He didn't put any heart into it."