SCP-173 looked at the ground of its cell. As always, it was strewn with blood and shit, along with the corpses of the most recent cleanup team. However, on this day, something different lay upon the stone ground. A small, red object, with two bumps on one end and a small point on the other, with a white, waving pattern curling around the edges.
Without pausing in its mad, frantic scratching of the walls, 173 picked up the object and peered closely at it. Beneath the stains from the floor, there appeared to be some sort of indecipherable scribbling across the object's front. What intrigued 173, however, was the picture on the front, for it was a picture of itself, standing in the corner of the cell, glancing over at the viewer. This puzzled 173 immensely; it knew many came into its cell with many strange objects, but it was not aware any were capable of capturing an image of it in such a fashion. Still, even after years of isolation, the sculpture recognized the image as itself, in some rudimentary fashion.
173 went about its usual business, dashing around the room and clawing at the walls, occasionally coming to a halt in the dead center of the room, so as to stare intently at the door and gather its thoughts of hatred towards those beyond. It did not let go of the object, though, for it still puzzled the statue. For what reasons, 173 could not say why, but there was a sense of mystery about this thing.
Hours later, 173 took to examining the object again. A little molding of the edges revealed an interior space, which it could open with a slight amount of effort. More of the strange scribblings were laid down on both sides of the inside flaps. Thinking they must mean something, 173 put its crude knowledge of human writing to use, trying to decipher the meaning behind the scratches. After an hour of hard work, 173 had managed to work out something that sounded like it might pass human lips. Putting all the information together in its head, it sounded out the words internally:
"Hach-aa-pehpeh-eeey… vvvvv-aa-llintt-aaaayyy-nehs… deh-aa-eeey…"
Complete and utter nonsense. 173 had a firmer, if still very loose, grasp of human speech than human writing, and this did not sound like anything a normal human being would say. Perhaps one with a mouth like its own, but certainly not one like those who kept it prisoner?
Could it be that they were mocking 173? Had it really come to that? They spend years upon years keeping it frozen in one place with their glances, locking it away, denying it the satisfying sound of a sickening crunch of revenge… and now they would mock it? Rage rose up inside 173; if they truly had descended to such cruel levels, then it would let them know just how cruel it could be in kind…
Fortunately, a thought of reason broke through the madness: It had not yet deciphered all the scratchings on the object. Perhaps if it were to do so, there would be a different course of action open. Of course, if they really were mocking it, then a wholesale slaughter would definitely ensue.
173 turned its attention to the scribblings on the left side of the object's interior. Two of the words, "to" and "from," were not hard for it to figure out: they were monosyllabic, and already ingrained into its limited vocabulary. So someone from the outside had sent something to 173, and wanted it to know the origination point of the object. A further examination of the words after "to" confirmed this suspicion. "Ess-Cee-Pee… Iee-vvv-eee" It didn't sound like much, but turning the phrase over and over in its head, it came to the conclusion that it was the name they had chosen to give it.
Shifting its attention back to the right-interior side, 173 noticed something else. The scribbling "Hach-aa-pehpeh-eeey" almost sounded like a word it knew. Something it always thought when snapping necks, something the people whose necks it snapped never seemed to be at all. Something like… "happy."
This gave 173 pause for thought. Someone beyond the door, one of its captors, wanted it to be happy. What could that possibly mean? The two words after happy remained incomprehensible to it, but they were surely just a further extension of the message of happy. So what could happy mean? Were they pleased with its performance as of late, and wanted to reward it for killing so efficiently? Did they understand now why it killed, and wanted to make sure it stayed happy by doing so?
Did they see it was unhappy, and that it wanted out?
As unlikely as it sounded, this seemed the most reasonable to 173's disturbed mind. It had served so much time, been held prisoner for so long. And it wasn't like it had been completely perfect before they took it in. Had these past decades been nothing but a long waiting game, one it simply had to sit through until the end? After so much time, it certainly hoped so.
And the shape of the object… 173 folded it back up, placed it on the ground, and tore into the bodies of the dead men on the floor. It took all three of them, but 173 was eventually able to extract a heart and, with much trial and error, mold it into a shape approximating that of the object. To 173, necks were the most fragile, and thus most important, part of the human body, but from what it had seen of the frightened, panicked reactions of those it had killed over the years, many held the heart up as most important. Whoever had sent this not only wanted 173 to be happy, but to connect that happiness with something distinctly human.
Having entirely stopped its routine of scratching at the walls, 173 stood there, in the middle of the room, staring at the card. There was more text to decipher on the front, but it was stunned by the potential implications of the interior of the card. For the first time in ages, it felt something towards its captors other than blind, seething rage, and cold, bitter hatred. Some deeper meaning was hidden here, some message that potentially meant its freedom. This surpassed the man seeking to die. This broke through to some deeper part of 173's… soul, it supposed.
It made a decision: It would spend as much effort as it took to decipher the writing upon the front of the card. If it turned out to be something negative, something mocking the sculpture, the aforementioned slaughter would take place. If it were some message of compassion and understanding… then it didn't know what it would do. But the lives beyond that door would be spared for another day. Sitting down for once, 173 set to work, spending hours staring intently at the front of the card, calculating to the best of its abilities the meaning of the scribblings upon the red, heart-shaped object.
At last, words and a meaning emerged. 173 stood slowly, stared at the door, and then went back to scratching at the walls.
***

At 0900 hours, Doctor Martin placed a Valentine's Day card in the pocket of D-3521, set for cleaning duty in SCP-173's cell. At 0906 hours, all three cleaning crewmembers were dead by an attack from SCP-173. Due to an internal mechanism jamming, the door to SCP-173's containment cell could not be reopened, resulting in the corpses of the cleaning crew remaining in the cell, and SCP-173 discovering the card. SCP-173 displayed highly uncharacteristic interest in the card, carrying it around the cell for several hours, and spending a significant amount of time sitting on the floor staring at the card. At 1700 hours, the internal mechanisms of the door were fully operational, allowing for retrieval of the bodies.

At this point, SCP-173 breached containment and attacked personnel all around Site 19, killing forty-two staff members at last count, including Doctor Martin. SCP-173 was restrained at 1727 hours by sixteen Foundation agents, and returned to its containment chamber shortly afterwards.