This is a protocol of Incident #066-DE-I1, mostly collected from recordings of security cameras and witnesses.
All original recordings, interrogation logs and a list of administered disciplinary measures is available in:
Preliminary note The following events where taking place in the night after Subject-4 has been found operational at urge of Dr. Baum, and has been released from quarantine. Most personnel who where not on guard-duty or taking part in nighttime tests, where in their quearters. In the Security Center, against the regulations, the 50th birthday of the guard ████ █████ is celebrated and cake is eaten. The guards on watch are only sporadic looking at the screens of the security cameras.
Begin of protocol
Subject-4 appears in his guard-uniform at the locker room in which the locker of SCP-066-DE is located and opens the code-lock with the standard-code for sector 11 (in sectors where multiple SCPs, suggested unable to escape and harmless, are contained in one room, usually one one code is used; this praxis has been changed after these events).
He goes to the locker of SCP-066-DE and casts the spell “Open Lock” on both locks; he has already carried out this spell in a test before and must have memorized it. He has brought the necessary components in a backpack and seems to be close enough to SCP-066-DE to cast the spell.
He takes SCP-066-DE out of the locker and goes to the elevator, without meeting someone on the hallway.
He takes the elevator to Level 5. The elevator accepts his clearance-number for the ride to Level 5 as he once was on duty at a Keter-SCP there, and the clearance has not been deleted, because no one doubted his loyalty.
When he is stopped from entering Level 5 by the guards in the access control, because he is not on the shift-list, he casts the spell “Fireball” which he throws in the guardroom, burning the three guards there to death and heavily damaging the equipment. The fire-alarm arouses some attention in the Security Center, but the guards are only paying attention to the fire, not the lone guard rushing through the hallways with a book in his hand and a backpack.
He is stopped by the two guards in front of the containment-cell of SCP-███-DE and after short discussion he casts the spell “Magical Armor”. The guards open fire but the bullets are bouncing off from him and are ricocheting into the walls an ceiling. He casts the spell “Energy-Bolt” on both guards, fatally wounding them. The firefight is not immediately noticed, because the fire in the guard room is extinguished by a fire sprinkler and a round of champagne in the Security Center.
A guard in the Security Center notices the guards lying in front of SCP-███-DE. After a short discussion and the detection of Subject-4, the officer of the guard sets off intruder alert and mobilizes MTF-DE4-𝔈 and MTF-DE4-𝔉.
Following the intruder-alert, Level 5 is set under lock-down, though Subject-4 is already in the hallway leading to the containment chamber of SCP-███-DE, where during Test No. 20 he had seen something very terrifying to him. He kills three of the four guards in the hallway with spells and a pistol he had taken from a dead guard. He forces the fourth with the spell “Pain” to unlock the door to the antechamber of SCP-███-DE's containment chamber, and kills him afterwards. He locks the door from the inside with the spell “Magic lock”.
MTF-DE4-𝔈 arrives the hallway leading to SCP-███-DE's containment chamber while MTF-DE4-𝔉 lays in reserve at the entrance of the sector, but cannot open the door. While it is send for a cutting torch, Subject-4 is identified on the monitors and Dr. Baum is called in who in turn sends for Subject-5.
Subject-4 lays a circle of an unidentified powder in the antechamber. By assessment of Dr. Baum and Subject-5 he is preparing the spell “Exorcism”, for which he is not strong enough, according to Subject-5. At his own request, Subject-5 proceeds to Level 5 with an escort. The cutting torch has arrived, MTF-DE4-𝔈 begins cutting open the door to the antechamber. All not required personnel is evacuated to the surface, in preparation of a general lock-down, and O4 is informed.
Subject-4 has finished the preparations and has opened the door to the containment cell of SCP-███-DE (which must remain unlocked according to its Secure Containment Procedures). While SCP-███-DE approaches the door, Subject-4 begins to cast the prepared spell. The circle flashes and the powder begins to glow. Thin glowing lines, like the veins on a leaf, begin to spread from the circle to Subject-4.
As they reach him they start spreading on him, which according to his body language and the screams heard by MTF-DE4-𝔈 seems to be very painfull. SCP-███-DE stands in front of the circle and watches with a curious expression.
As Subject-4 is fully covered, he starts morphing. He grows to a size of circa 3 m and rips of his clothes, falling off in burning scraps; where his skin is visible through the lines, it starts changing color to a reddish brown; with a loud crack his lower legs break to a second, backwards knee; black claws are growing from his fingers and toes; his face sinks so the skull underneath is clearly visible, sooty flames are burning in his eyesockets, two horns like from a tragus are growing from his skull above his ears. Based on the theory that this creature is no longer Subject-4, it is classified SCP-066-DE-2.
SCP-███-DE tries [REDACTED], what seems to have no effect on SCP-066-DE-2. SCP-066-DE-2 grabs SCP-███-DE, tears open its chest with its claws, takes its two hearts out and consumes them.
Meanwhile MTF-DE4-𝔈 has cut open the door, SCP-066-DE-2 drops SCP-███-DE's body which does not regenerate as usual and turns to the MTF. The MTF opens fire but the wounds inflicted by their bullets are closing immediately.
SCP-066-DE-2 attacks MTF-DE4-𝔈 and kills 9 of its members with its claws and another 5 retreating members with a Fireball, which looks and works like the spell.
O4 orders lock-down of the whole site and mobilizes the remaining Forces of Site-DE4 and two alarm-MTFs of Site-DE8.
MTF-DE4-𝔉, by which now also Subject-5 and his escort have arrived, is separated from SCP-066-DE-2 by a steel-reinforced door due to the lock-down, which sets the door aglow with a Fireball and tears it open with its claws. Subject-5 passes behind SCP-066-DE-2 while this is slaughtering MTF-DE4-𝔉 and the escort.
He rushes to the antechamber or SCP-███-DE's containment cell, where the exorcism is still prepared and renews the circle with the rest of the powder. He calls the name of Subject-4. Then he leaves the circle and casts the spell “Exorcism”; Subject-4 has let SCP-066-DE fall during his transformation, and has left it in the circle. The circle again starts to flash and the powder starts glowing, though now blackness spreads inside, which as the whole circle is filled, starts wafting like thick black smoke on the floor.
SCP-066-DE-2 appears in the doorway, it is splattered in blood, dripping from its claws. It stares into Subject-5's eyes while it slowly, as if it was fully aware of what it does, enters the circle. The blackness creeps up on it and as it is fully covered, it collapses and dissolves into fine soot; the circle ceases to glow. SCP-066-DE-2 has vanished.
After one hour the lock-down of the rest of the facility is revoked, after 6 hours four MTFs are storming the Level and searching it according to the standard-pattern for Keter-breaches. Subject-5 lets himself get taken into custody without resisting. All victims of Subject-4 and SCP-066-DE-2 are dead and are getting cremated. As SCP-███-DE is not regenerating after a period of quarantine, and starts to decompose, it is declared neutralized and its remains are also cremated. Subject-4 stays missing and is declared dead.
End of protocol
Following this breach, the security apparatus has be reorganized, and many new and more strict regulations and disciplinary measures have been established. Subject-5 has been [REDACTED] on own suggestion, to be available for containment protocol 𝔐𝔞𝔤𝔲𝔰, in an emergency.