The way in which triggered abilities have been dealt with has changed
  dramatically throughout the history of the game.

  When any instruction is followed in the game, it may match the trigger
  event of any number of triggered abilities.  Each time this happens,
  the triggered event triggers.  When a player is in the process of
  gaining priority to play spells and abilities, players put any triggered
  abilities that have triggered onto the stack.  First the active player
  adds all the triggered abilities that he or she controls, in the
  order of his or her choice, and then the non-active player does so.
  With multiple non-active players, players go in turn order.

  With this system, triggered abilities never go onto the stack while
  another spell or ability is resolving.  They always wait until a
  player is about to gain priority.

  Some damage prevention effects have "side-effects", extra things that
  are written along with the damage prevention:

  Brace for Impact  {4}{W}  Instant
/ Prevent all damage that would be dealt to target multicolored creature
  this turn. For each 1 damage prevented this way, put a +1/+1 counter
  on that creature.

  These are not usually triggered abilities.  They just happen as part
  of the event that would have dealt the damage.

Some parts © 2009 Advameg, Inc.