C³ - CubexCursedxCurious(2011)

Original title: C³ -シーキューブ-

A high school student named Yachi Haruaki receives a mysterious, super-heavy black cube from his father overseas. That night, Haruaki wakes up to a suspicious noise in the kitchen, and he discovers a fully naked female thief of rice crackers. The girl, Fear, is the first of several surprises that Haruaki receives.