This is likely a "leaked" or curated collection.
Repacked games, specialized industrial software, or "all-in-one" utility suites. mda.monsterrrrrrr.pl.part18.rar
This indicates that the original data was too large for a single upload and was split into many pieces. To access the contents, you generally need all parts (Part 1 through Part 18, and likely many more) saved in the same folder. This is likely a "leaked" or curated collection
If you are unsure of the contents, extract the files inside a Virtual Machine or a "Sandbox" environment to prevent any potential scripts from affecting your main operating system. Do you have the other parts of this archive, or To access the contents, you generally need all
Before extracting, run the file through VirusTotal or a local updated antivirus. Note that scanners often cannot see inside the RAR if it is encrypted.