Complex sentence: Common special effects included aiming the camera into a monitor to creat an "infinity" image of an image, possibily a dancer, appear to have their image repeated behing them many times and get smaller and smaller as it repeated.
Split into simpler sentences: Common special effects included aiming the camera into a monitor. The image, possibily a dancer, appears to have their image repeated behind them many times and get smaller and smaller as it repeated.