It makes such an awful sound. There's no dramatic FIGHT music here, no explosions, just the raw, ugly thud of his fist against flesh and the gasp as Barnaby gets the air driven out of him. He tries not to think of the damage it must be doing. All the soft parts humans have inside them.

Do intentions count, for physical attacks against a human? Does it matter that he doesn't want to do this?

...no. Of course not. Stupid to hope so. It won't matter, because he isn't the attacker here. He's the weapon. Nothing more than a blunt instrument.

And you've done worse. The voice in the back of his mind sounds just like Chara, for a moment. Of your own free will, you have done worse and enjoyed it. Don't act so shocked.

But it's different, without the high of LOVE and self-justification driving him. He doesn't want this.

The room is starting to blur around him. Mettaton didn’t think his horror could grow any deeper, but it does, just a little, as he feels shimmering magical energy start to pool beneath his eyes. Not even strong enough to form a bullet. That was Blooky's thing.

Of course he can still cry. And he can't even raise a hand to wipe it away. The humiliation only makes it worse.