Glossary
Encoded PowerShell
A PowerShell command passed as Base64 of UTF-16LE text with -EncodedCommand, often used to hide the real script in scheduled task arguments.
powershell.exe -EncodedCommand <string> accepts "a base-64-encoded string version of a command" (about_PowerShell_exe). The string is Base64 of UTF-16LE text, and PowerShell accepts abbreviations such as -enc or -e. Decoding reverses both steps: Base64, then UTF-16LE. For example, VwByAGkAdABlAC0ATwB1AHQAcAB1AHQAIAAnAHMAeQBuAHQAaABlAHQAaQBjACAAcwBhAG0AcABsAGUAJwA= is Write-Output 'synthetic sample'.
Administrators use it too, to avoid quoting issues, so decode and read before judging. See detecting malicious scheduled tasks.