Found it! Shinigami Doll.

Hi, I’m looking for a horror manga anthology I read many years ago. I suppose it was published in 2012 or earlier.

The first story is about a girl who’d always take her anger out on her plush bunny, until one day the bunny decides to take revenge and they switch bodies. The bunny-turned-human goes to school and murders a classmate. Then they switch back into their original bodies.

The second story is about a high-schooler who has a crush her classmate/schoolmate. They start dating (he just broke up with another girl) and soon after the boy becomes possessive, trying to control her appearance. She cuts her hair to defy him. Then he kidnaps her, dresses her in his dead mother’s dress (talking about how the previous girl was too big for it), and locks her into a giant glass box where he intends to keep her forever as a doll.

There might be more stories (I’d love to read them if there are). Does anyone have a guess?