I'm an experienced bash user (scripting since about 2013), and I love the idea! I think that I can make use of some native linux utils such as nmap and netstat to make it look like it's doing something. Depending on the intended use in the scene, I can either make it run by itself and/or be interactive at times, i.e. input a fake password or something along those lines.
As for how it would look like, I can make some colorful graphics, including ASCII-art and/or ANSI-art (blocky images in terminal), maybe some flashy ACCESS DENIED notices. Besides that, I'd be able to style the OS to make it look more hacker-y with dark themes and pixel-y fonts.
I'll be able to finish it in around two to six hours + time for tweaks/fixes.
Looking forward to working with you :)