Kachikucchi

After his mother dies, Tenma Miyamoto, a lonely boy, is sent home to a strange but adorable creature called "Chikucchi." He builds a friendship with the creature to fill the void in his heart, but one day, his father, who is after his mother's insurance money, shows up to his house and bullies the creature. A bloody, soothing, killer suspense story about a mysterious creature!

(Source: Shinchosha, translated)