When a player enters a square that contains a chest it will magically open. It will contain either the ball or a trap.
If a player moves onto the chest that contains the ball (including being pushed into it) he must attempt to pick it up, unless he is not standing as he enters the square, e.g. as the result of a block or has No Hands. The pickup roll is an AG roll with a +1 modifier. If one of your players fails a pickup attempt in your turn this causes a turnover.
If the chest contained a trap the player is knocked prone, make an armour roll. Adjacent players are knocked over on a 4+, make armour rolls for players knocked over as if knocked down by a player with Mighty Blow. If one of your players is knocked down by an exploding chest in your turn this causes a turnover.
A player that is Knocked Down into a chest (e.g. blocked, failed dodge/GFI) will trigger the opening of the chest. If the chest contains the ball it will scatter and the knocked down player can not gather it. If the chest contains a bomb make the armour roll for the knocked down player, but treat it as if it were made by a mighty blow player. If the knocked down player was blocked into an explosive chest by a player with mighty blow add 1 to both armour and injury rolls.