Invasion is a floor in stage 7. It is annoying and also very fiddely; difficult for a game in which you don't have a controllable camera. The whole floor is fairly thin, however the board on it's own would be very easy (save for the very thin, straight part right at the end). The reason this stage is tough is because it is littered with bumpers, some stationary, some dynamic. Without good timing, precision and steadiness, this floor can eat lives in challenge mode.