From kalilinuxtutorials.com
PolyShell is a script that’s simultaneously valid in Bash, Windows Batch, and PowerShell. This makes PolyShell a useful template for penetration testing as it can be executed on most systems without the need for target-specific payloads.
It is also specifically designed to be deliverable via input injection using a USB Rubby Ducky, MalDuino, or similar device.