Mimic Awakening

In his sleep, a mysterious figure appears in a young man's room. Suddenly, the mysterious figure ends his life, triggering his reincarnation to the other world where magic, monsters, and gods exist. Upon waking up from a sleep, the protagonist finds himself in a dungeon and discovers that he has reincarnated as a mimic, one of the weakest monsters in the new world. In this world, there is a rare power unique to a few individuals called Awakened Abilities, and he is equipped with it from reborn. As an awakener, he learns that he has the ability to absorb magic crystals and gain abilities and forms from anything he devours. While tracking his way out of the dungeon, he meets a powerful mage with alluring beauty. That encounter paves his way to become stronger and more powerful faster than he expects. Little that he knows, his sudden appearance breaks the timeline that causes changes that gradually ripple throughout the world. — Description from novelcodex.org