The Hand.

One night, the main character “Bongsoo” and his wife, encounter a grotesque looking hand sticking out from the toilet in their bathroom. The “hand” protruded out of the toilet seems to be very still, like a severed limb hanging low. The wife, security guard and 911 crew gather in the bathroom, one after another, to identify this strange looking “thing” but all of a sudden find themselves struggling for their lives as they try to fight against it.