The stack is the most important behind-the-scenes aspects of Magic – yet, it wasn’t always there.
Originally, things just happened. The stack as we know it today wasn’t added until 6th Edition, and was designed to deal with the crazy stuff that happens in the game.
Essentially, every card that is cast and every activated and triggered ability uses the stack, whether it be a creature, instant, sorcery, enchantment, or artifact. In response to a card being cast or an ability being activated or triggered, every player may respond as long as another player doesn’t hold priority.
Priority: the right to play a spell or ability, or take a special action. Players cannot play spells or abilities or take special actions at a time when they do not have priority. The player with priority may put as many spells or abilities on the stack as he/she wishes to, but before anything can resolve all players must pass priority without adding anything further to the stack.
For example, you can play a bunch of cards out of your hand without even passing priority – as long as you’re playing cards at instant speed and not sorcery speed.
Priority is probably the largest part of the stack, as it determines what order things get to happen, and the player with priority gets to decide the order on triggers.
Let’s say you have a 2/2 swinging at an opponent sitting at 12 life. They assume they can take the 2, and let your attack go through.
During the damage step of combat, you use a creature with flash from your hand – Briarpack Alpha.
So, at this moment, the stack is just Briarpack Alpha in response to the beginning of the combat phase. You don’t have anything else to say yet, so you pass priority, and your opponent has no counterspell. Briarpack Alpha resolves.
As Briarpack Alpha enters the battlefield, his enter the battlefield ability triggers, amd you target your attacking 2/2 to make him a 4/4. With nothing else, you pass priority.
Your opponent responds to the ability by dropping a Doom Blade on your 2/2, which is now a 4/4.
Your opponent passes priority, and then you play Ranger’s Guile.
So on the stack at the moment is Briarpack Alpha’s enter the battlefield ability on the bottom of the stack, then Doom Blade, and then Ranger’s Guile on top. You pass priority, and they have no response to your Ranger’s Guile, and your creature becomes hexproof and gets +1/+1. As your creature is now hexproof, their Doom Blade loses its target and fizzles. Then, finally, Briarpack Alpha’s ability resolves, and your opponent will soon be taking a 5/5 hexproof beater to the face.
The next thing we’ll talk about are things that do not use the stack – in part 2.
Until next time.