Item #: SCP-XXXX
Object Class: Euclid
Special Containment Procedures: Object is to be kept in a standard humanoid containment room decorated to appear as a child's bedroom including one  pink play vanity with matching stool, and one  pink child sized bedframe with matress and bedclothes in the same fashion (See addendum XXXX-A). No sustenance is necessary as per normal protocal for inanimate objects. SCP-XXXX-1 is not to be removed under any circumstances (See addendum XXXX-B) except during authorized lab testing supervised by at least one research specialist with security clearance 2 or higher. D-Class test subjects may be used, although with some restrictions (See addendum XXXX-C).
Description: SCP-XXXX is a key-wound music box of unknown origins, it is made from wood similar to Rowan, but all DNA testing done on wood samples points toward an unidentified subspecies. There is a gold band with floral pressings wrapping around the center of the box, with an inscription in [REDACTED] translating to "Be not afraid child, the Shadows shall protect you." The box has a small keyhole on the front into which SCP-XXXX-1 fits.
SCP-XXXX-1 is the matching key to SCP-XXXX and is a small gold key with a heart shaped head, the key itself has no anamolous effect without the music box and seems to simply be an activator.
Object discovered during a routine sweep of reported hauntings, SCP-XXXX was located in an abandoned house that had previously been the location of a foster home for abbused children. The house had fallen into extreme disrepair, but the room in which the object was discovered was in pristine condition. As the team on site entered the room the room SCP-XXXX began playing, each team member reported having heard a different melody, leading the team to recognize it's potential anomolous nature. Upon contact with SCP-XXXX all members of the team reported sudden movement in the shadows of the room, accompanied by whispers and children's laughter, after a few moments the activity ceased and the object was brought in for further study, interestingly the entire house collapsed when SCP-XXXX was removed from the property.
Addendum: (Case XXXX-A) During an experiement by Dr. M█████ the box was removed from it's containment room and taken to another empty room of similar size, Dr. M█████ left the room briefly to deal with a containment issue of a more dangerous SCP and upon return discover the previously empty room had furnished itself in the fashion mention, prefurnishing of the room no longer considered necessary.
Addendum: (Case XXXX-B) An experiment conducted by Dr. Q██████ involved having a D Class test subject remove SCP-XXXX-1 from SCP-XXXX, upon removal of the key the test subject reported hearing a loud howling or screeching sound and feeling a sense of impending disaster. The two objects were returned to their room seperately and placed on surfaces directly opposite of each other, later that night the test subject who removed the key was heard screaming, he was found lying face up with his heart removed through a keyhole shaped opening in his chest. SCP-XXXX was later found with SCP-XXXX-1 returned to it's keyhole and a new inscription on it's gold band translating to "Return my heart to me each night, or pay with your own." This prompted an update from Safe classification to Euclid
Addendum: (Case XXXX-C) Any and all class D personnel assigned to SCP-XXXX must not have any history of violence against children, upon entry of a D Class test subject (Caucasian, 35) who had previously [Redacted] no fewer than 7 [seven] children before his arrest the SCP began playing on it's own as was expected, as he approached it the researcher reports seeing 10 [ten] child sized humanoid shadows surround the subject, and one adult sized humanoid shadow in the shape of a woman in an ornate dress appearing a short distance in front of him. The larger apparition then walked slowly towards the subject while the smaller apparitions held him in place, upon reaching him the large apparition reached into the subject's chest and removed his heart, the smaller apparitions then [REDACTED] the body and each vanished leaving no trace other than the mangled body with a keyhole shaped wound and a missing heart. Similar results came from three other instances of D Class subjects with histories of violence against children.