I looked at the table, and saw one of the cookies was missing. I wondered what happened to it.

Is there a style of drawing that only reveals Koishi when you stare at a certain part of the picture? Not the blurring kind or incredibly small; normal looking like this, only with that trick.

Transparent and when you see it tags?

Wait. Is there supposed to be some trick here? I noticed Koishi's hand almost immediately.

Ipswich67 said:
Wait. Is there supposed to be some trick here? I noticed Koishi's hand almost immediately.

She's manipulating the subconscious of everyone nearby not to notice her. Though, she might want to put some more effort into it.