What is Ethernet Adaptor (wc5) In my Network Preferences panel, I've just noticed a network type I didn't see before.

The name is "Ethernet Adaptor (wc5)" (note it says Adaptor and not Adapter). It has an IP, it's yellow, and it says "Ethernet Adaptor (wc5) has a self-assigned IP address and will not be able to connect to the Internet."

What is it? Where does it come from? I am connected via WiFi - and, probably not a coincidence, I have internet issues right now (some sites work some don't). 

What is happening?

EDIT: Disabled this network adapter, and now Internet flies. I don't know what it is and how it got there...
The (wc5) is probably from Wirecast. Do you have it installed?

It may have added an interface so it can stream and grabbed what it thought was an Ethernet interface but was actually your WiFi interface.