Ghost Becky/Fourth Wall Break/Illusion Break are all ways to describe discrepancies in the format of Video Games Awesome due to the placement of the camera and the chatroom. Ghost Becky is mostly used when Becky
Walking off screen

Fraser makes an example of Johnny about the dangers of walking off screen.

seemingly steps onto the chat, due to the nature of the green screen. While she's over the chat, she is transparent, hence the name Ghost Becky. Fourth Wall Break is a term for when the head or arms(but mostly head) of a cast member leaves the screen or view, showing that the set up isn't as casual as you'd believe. Illusion Break is an alternate term for either. Kyle is a common offender in terms of breaking the Fourth Wall.