plugin-container cpu
A process called "plugin-container.exe *32" was taking up 99 of my CPU (location: C:\Program Files (x86)\Mozilla Firefox). WHY??? :(
Alla svar (1)
Yes, it is a separate process for Firefox. More info here. If it's clogging up your computer, then perhaps you should disable some plugins - you may not need all of them. Also avoid running too many tabs at the same time, especially ones with flash (e.g. gaming websites or youtube).