Per 
I understand that many of you may be uncomfortable with or even dismissive of this proposal if for no other reason than that it involves putting more than two SCPs in a room together, however I strongly believe I can assuage any concerns personnel may have. To be clear I am proposing that both SCPs 173 and ●●|●●●●●|●●|● be utilized in this attempt, however ideally 173 would be unnecessary but I find that unlikely. Additionally we are assuming that matter taken by ●●|●●●●●|●●|● is either entirely destroyed or removed from our universe in some way, if this is not the case then perhaps it could be replaced by another matter destroying entity or object.
I have selected these two for several reasons, the first and most important being that their containment is very straight forward and provided that the proper precautions are taken their individual recontainment should be of little issue. This is true even in the case of major breaches as 173 needs merely to be observed to be rendered inert and ●●|●●●●●|●●|● is only a threat to those who speak information regarding it aloud or to mediums with said information written on them. The second major reason is that each of them have had a high degree of success in dealing with SCP-682 individually. However i believe that ●●|●●●●●|●●|● was majorly underutilized previously and is one of the few SCPs which really seems to have any chance of fully eradicating or at least removing SCP-682. Additionally these two have a very low chance of interacting with each other in any way, especially if they are utilized intermittently.
It is important to note that to date, while physical trauma is one of the most effective ways of incapacitating 682, there seems to be no chance of any amount of physical damage actually terminating it. Keeping that in mind 173 has been successful in fully incapacitating 682 in the past and is one of few SCPs that 682 has been incapable of matching and defeating in combat. Therefore in this test we'll be treating 173 as a means of immobilizing 682 in order for ●●|●●●●●|●●|● to be more effectively utilized rather than expecting 173 to have any chance at "killing" SCP-682.
Procedure details
A specialized room should be prepared, equipped with multiple (two or three could probably suffice but there's no kill like overkill and the faster we carve the less time 682 has to adapt and regenerate) ceiling mounted lasers capable of carving into SCP-682 just as in the previous experiment involving ●●|●●●●●|●●|●. 682 should be fully restrained (perhaps powerful elecromagnetic "cuffs" on each of the joints of the subject's limbs as well as around the torso and neck, all of which could be magnetized to the ground, forcing it into a "spread eagle" position). We then use ●●|●●●●●|●●|● to begin removing 682's flesh piece by piece, beginning with the head and hopefully eventually fully eradicating the creature with repeated ●●|●●●●●|●●|● use. As it should be considered extremely likely that SCP-682 will find a way to break out of whichever method we use to immobilize it SCP-173 should be preemptively moved to a room conjoined with this one and should only be released in the scenario that 682 does manage to free itself from restraints. This should be at the very least an effective means of impeding 682's escape.
The ideal outcome at this point would be for 173 to damage 682 enough to render it immobile at which point observation of the room should be resumed and utilization of ●●|●●●●●|●●|● can be safely continued. However it should be assumed that 682 will develop multiple sets of eyes in an attempt to neutralise 173 as it has done before and in order to deal with this I would suggest highly pressurized acid spray consistent with 682's typical containment procedures as well as utilization of the aformentioned lasers. This method would also be useful even if the subject is in motion or otherwise preventing ●●|●●●●●|●●|● from being used to remove these parts. At this point we should repeatedly alternate between removing 682's flesh with ●●|●●●●●|●●|● and immobilizing with 173 and/or acids as appropriate. In addition while 682 is immobilized if restraining it again is possible it would make all of our lives much easier.
Finally for full termination to take place we must assume that 682 can regenerate from even a single surviving cell. This means that following thorough incindiary and acid spray decontamination of the entire room we should use ●●|●●●●●|●●|● on the entire flooring and even the walls, especially anywhere where 682's blood has fallen. SCP-173 should also be decontaminated using powerful incindiaries and acids (because of its significant resistance to any type of damage and the importance of terminating 682 I believe preventing 173 from taking damage can be considered less of a priority than fully eliminating 682 but that's really up to O5), I would recommend mucous from SCP-811 for this "cleaning up" process as it has little to no effect on inorganic matter, however it is important to note that 682 has developed an immunity to the mucous in the past and has control over whether its body is considered organic or inorganic so other acids and incindiaries should still be used in tandem with 811.
This entire attempt is based on putting 682 out of commission in one way or another repeatedly until all of its biomass can be eradicated so personnel should perform every component of this operation extremely thoroughly but also swiftly to prevent 682 from having time to compensate and regenerate.
Here is a list of possible 682 adaptations and contingencies for them, feel free to add if you come up with any I may not have considered.
-Anti laser bone shell/highly refractive covering/other armored carapace
- Should laser engraving be rendered ineffective keep in mind that the information does not need to be carved and writing on 682 with a marker would suffice, although it would likely be somewhat less effective but ●●|●●●●●|●●|● only needs to remove the laser proof material so that engraving can be resumed.
—For this purpose I believe Mr Deeds (SCP-662) may be the ideal choice to perform this task as he is helpful, capable and willing to undertake any task even unto his own death. In addition due to the nature of 662 the risks of collaboration or a joint containment breach can be considered minimal or even non-existent. 662 may be extremely helpful in multiple roles in this procedure such as restraining 682 while it is recovering from 173's onslaught.
-682 breaks ceiling mounted lasers or acid hoses
-We should obviously have replacements on standby, in addition we could have piloted or automated mobile machines equipped with the same lasers as well as writing utensils prepared to enter the room at any time. Alternatively 662 would be an excellent option in this scenario as well.
—If we use automated writing machines (which would be ideal as they could carve/write much faster than any pilot could match and even be doing so in multiple places at a time) we are faced with yet another problem as any data storage unit with information on ●●|●●●●●|●●|● will be subject to its abilities. We may be able to circumvent this by using a rudimentary graphing system where the machines simply "connect the dots" rather than programming them to write words on 682. This is only a theory but I think it's a fairly solid one.
- It is possible that in order for ●●|●●●●●|●●|● to be used the information must be written and not drawn (meaning that while the information appears as written word it was in fact drawn and therefore counts as a picture rather than writing) as in the case of the graphing system I've proposed but if this is the case we can just use pilots instead. Additionally this technicality may allow us to catalogue and store detailed information on ●●|●●●●●|●●|●.
-682 develops the ability to "observe" 173 without the use of eyes or other sensory organs
-This doesn't seem like something that would need to be addressed ordinarily but 682 has surprised us in similar fashion on multiple occasions in the past. There are two possibilities here, either SCP-682 develops a new system of observation by converting each cell of it's body into a makeshift antennae or maybe it could manifest some form of esp (honestly anything goes with this thing) which could be used to observe 173, this way we wouldn't be able to target individual organs to free 173.
—In this scenario it would certainly be difficult to keep 682 incapacitated, our best bet here would likely be to smother it in acids (possibly SCP-811 mucous and/or SCP-075's secretions, both of these may be safely collected using SCP-294).
-682 prevents 173 from perceiving it as a target
- While it stands to reason that if SCP-682 were capable of this it would have done so in the past, we've been surprised before and as 682 has previously shown, it can manipulate many of the qualities of its cellular makeup. It can be organic or inorganic, live or dead or neither or both etc. Unfortunately the only real contingency for this scenario is to have another SCP capable of incapacitating 682 on standby, such as SCP-524. I would like to go on record stating that I don't like this, instead I recommend that in this situation our priority should be recontainment, let's try not to let it out for the sixtieth time.
— Acid flooding should work given enough time.
-SCP 682 somehow becomes immune to ●●|●●●●●|●●|●'s effects
- While not likely this should be considered very possible, in this case we are once again back to using acids. Acid may seem like a little bit of an unimaginative solution but it continues to be a useful weapon against this thing so we should use it whenever it can be helpful and whenever our options are exhausted. If this adaptation does occur our priority will be incapacitating 682 to restrain it and switch back to a permanent containment unit.
-SCP-682 develops an ability to siphon off the energy of the electromagnets
-A kill switch should be available to deactivate these at any time but this adaptation seems unlikely as they will not be used to harm 682 and its other adaptations usually counteract a direct threat.
Other than these possibilities I don't see many openings for error in this attempt outside of the death of 173 or ●●|●●●●●|●●|●. While it may be possible that 682 could kill either of them in its current state it seems unlikely, firstly because if it were capable of this it would likely have done so previously (at least in the case of 173, 682 was effectively restrained in its encounter with ●●|●●●●●|●●|●), and secondly it seems unlikely that its regeneration will be able to account for both of these threats in addition to the acids and damage from lasers. If 682 does manage to survive this attempt it will be because it develops a higher degree of adaptability than we have seen or because ●●|●●●●●|●●|● is totally incapable of permanently killing 682.
