D-12-3 was a member of Mobile Task Force D-12 "Mud Slingers" who was killed during their team's expedition into SCP-1730.
SCP-1730 exploration[]
D-12-3 was dispatched alongside the rest of their team in front of SCP-1730's main entrance, and was the third to respond in the mic check conducted by D-12 Captain. Upon entering the poorly-lit main lobby, Three announced as they turned on their shoulder-mounted light, an idea that was praised by the captain and copied by the other team members.
When MTF D-12 descended down a service elevator to Level B3, D-12-3 was tasked with D-12-1 to survey a perpendicular hallway at the end of the main corridor. Three began working with One in disassembling a pile of desks they found barricading the corner hallway.
The two briefly stopped as Cap told One to hold their position, and that D-12-4 had discovered a body. After being cleared to continue, Three and One surpassed the barricade, finding more sludge and bodies in the second hall. As One reported the cadavers, Three alerted their partner that one of the bodies had moved, due to a leech inside of it. After the snake-sized leech burst from the corpse's mouth, Three followed One's command and opened fire on the annelid threat, hitting one of the corpses in the torso. Prompted by Cap's demand for a report, Three described the leech-turned-red streak as One inspected the corpse pile.
Reuniting with Four and Cap, Three followed their team as they found that the hallway corner had fared a spatial anomaly, and had lost contact with D-12 Two and Five. As the team stopped to break open a locked door, D-12-3 voiced as they noticed what seemed to be the sound of someone shushing D-12-1's countdown. As One kicked the door open to a scared, naked human with flaming ears, Three was cut off mid-swear as the the entity combusted without a sound, critically wounding Three, killing their team, and melting their body cameras.
Thrown to the floor, D-12-3 was laying prone as another one of the leeches approached them. Thirty seconds after the explosion, the operator at Provisional Site-23 Command recognized that D-12-3's microphone was the only one left intact, and attempted to garner a response from the remaining agent. Three was unable to formally respond, as the leech had entered their mouth and began to devour their abdominal organs. The last D-12 agent's dying moments were recorded as they choked on their own blood and esophageal viscera.