Usually In the main round, anytime a team draws a "stopper" from their hopper in front of them then they will forfeit their turn to the opposing team. In the Engvall version, if one of the teams grabs a stopper ball from a rack besides them, then they'll still lose control to the opposing team while the word "STOPPER BALL" would be seen on a video screen in front of them with the word "STOPPER" in red along with the word "BALL" in white. The original 1987 version also had red balls, but they were seldom seen up close.