Posting here because I'm very obviously not disc staff.
GDRexRacer77 does not match any existing user name recently posted their sandbox for review in someone else's draft thread, seen here. They later made their own thread and edited their post after Zachary called them out. Whilst this is all newbie cluelessness, it is the contents of the sandbox that are in question.
The first tab of the sandbox, titled "Angel Serum" is pretty much word-for-word copied from Roget's SCP-1853, with only some changes (thanks to DrBleep for pointing this out to me).
From GDRexRacer77:
Special Containment Procedures: All known samples of SCP-XXXX are to be contained in airtight containers under restricted access at Site-77 in Storage Locker 663. When in containment, SCP-XXXX is not to be used on D-Class personnel or any other human subjects for testing purposes. Only chemical analysis testing is approved. When being tested, a small amount should be stored in an aerosol dispersal system. If modern human science knows and can prove about SCP-XXXX in the near future, then it must be distributed to the public for medical use
Description: SCP-XXXX is a bright green human-derived serum containing a mixture of unidentified proteins and chemical compounds. When not being applied to an organic object, SCP-XXXX displays no cosmetic anomalous properties, and is visually identical to bright colored green water. When applied to a living subject, SCP-XXXX will reduce the age rate by 10%. It will also make the subject immune to any sort of disease/illness.
From Roget:
Special Containment Procedures: All known samples of SCP-XXXX are to be contained in airtight containers under restricted access at Site-77 in Storage Locker 663. When in containment, SCP-XXXX is not to be used on D-Class personnel or any other human subjects for testing purposes. Only chemical analysis testing is approved. When being tested, a small amount should be stored in an aerosol dispersal system.
Description: SCP-1853 is a green human-derived serum containing a mixture of unidentified proteins and chemical compounds. When not being applied to an organic object, SCP-1853 displays no anomalous properties, and is functionally identical to water. When applied to a living subject, SCP-1853 will noticeably enhance the performance of the individual subject in a competitive environment.
The image in the sandbox article is also very similar, whilst not identical. The rest of the articles in the sandbox do not appear at first glance to be plagiarised.