A trapping zone defense that positions one player at the top of the key and four players in a diamond formation behind him. The goal of the defense is to force the ball into the corner where the defense can aggressively trap.
The amoeba defense is typically used to defend a skilled post-up player because it usually puts two defensive players on him at all times. However, this defensive formation is high risk-high reward. If the defense can successfully trap the ball in the corner, the offensive player will be pressured to make a bad pass. However, once a smart offense recognizes the defensive scheme, he can basically steer clear of that area of the court to avoid getting trapped.
Very few teams employ the amoeba defense, and even those who do only use it intermittently. The most famous team to play the amoeba defense is the 1990 NCAA National Champion, UNLV Running Rebels, which was led by eventual NBA players Larry Johnson and Greg Anthony.