Kyouran Kazoku Nikki EP20 - Forest of Vitamin C

When Chika gets bitten by a hamster she has flashbacks to memories of her first pet, a gigantic demonic monster which is actually just a cursed man. Although Chika tried to use him against the House of Oni he refused. When soldiers attack Chika searching for this monster she finds out there are connections between her first pet and her new best friend Hijiri.