Board Thread:Speculation House/@comment-14138255-20151213162620/@comment-25086632-20151213165431

What seems to be going on with the Mercury and Fake Yatsuhashi thing is Emerald has some sort of hallucination power. She can make a single individual see things happening in a way they aren't.

So she made Coco hallucinate a Yatsuhashi, and made Yang hallucinate Mercury attacking her.