If anyone's interested, “Parasite (F119).DMS” needs to be unpacked with a tool such as xdms (Linux), The Unarchiver (Mac) or WinFellow (Windows).
I didn't test the Mac and Windows tools yet, but on Linux, I tested and it works.
Here's the steps to use it on Linux:
First, if your distro has the tool in its repositories, you can use a command such as:
$ sudo apt install xdms
Then open the terminal window and navigate to the folder with the file ( $ cd path/to/file's/location ) and, if you didn't change the file's name, type the following command:
$ xdms u "Parasite (F119).DMS"
This should output an .adf file which can be used in the emulator of your choice.