Default [Q] Spoofing OS

Technical question. In theory, what would I have to do to make any device on a wireless network see this phone as a PC instead of a cell phone, and if you know, how it would be done, even if the device seeing the phone is probing for that sort of thing with something like nmap. I'm considering spoofing my MAC address but I don't believe that would work as I don't know if there's some way to tell using registered Mac Addresses or not. This is a for-fun experiment a friend and I are doing.

Device - Verizon Galaxy S4