I Reincarnated as a Hero, but Turned into a Mimic Chest. What Is This Supposed to Be?

I opened my eyes and found that I had become a newly hatched mimic. I distinctly remember being summoned to become a hero! What on earth is going on?! Whose hero is a mimic?! How can anyone look at me and think I'm a hero?!

And the world is unbelievably cruel. I can only struggle with all my might to survive while searching for the truth hidden in my shattered memories.