check this Undetectable Mouse Jiggler

What is that? 
Mouse jigglers are useful in IT fields to stop a computer from activating a screensaver in a presentation in order to prevent a computer from shut down for a forensic investigator for a wide range of purposes.

Why did you do it? Why did you?

Digispark is an accessible development board powered by a 16MHZ, 6K usable, ATtiny's 85 microcontroller that connects to a host via USB. These panels are incredibly capable and can be used for a variety of tasks, including mouse and keystrokes.

What's special about it?

Low cost and usability. Being a hardware and basically a mouse/keyboard that moves the mouse (and keystrokes). Wheren Digispark shines is a simple attack on the human interface device that uses a target to inject plenty of code for a short period of time. This can be anything from a simple Netcat backdoor to a payload ransomware — where you can convert many scripts for USB Rubber Ducky to make other payloads.