Instead of looking it up I felt like chatting it up. Who gets first priority at the beginning and ends of phases? And what's up with not being able to react to an instant played by the attacking player when applying damage from unblocked creatures?
1) The active player (the one who's turn it is) always gets first priority then priority passes in turn order, if there are more that two players. The shorthand is APNAP. Active then Nonactive.
2). I'm not sure what you mean by this, since there is a chance for players to respond after blockers have been declared, and the defending player CAN respond to and instant played by an attacking player.
I was informed that once attacked, if I chose not to block, there is some kind of priority where the attacking player can then play an instant/ability (say giant growth) and I as the defensive player cannot respond. A few people vouched for this at a ore release and said it was a more recent rule change
Let me see if I can explain the structure of the attack phase:
1) Beginning of Combat Step
-determine defending player
-the active player gets priority. Players may cast spells and activate abilities. (AKA fast effects)
2) Declare Attackers Step
-determine attackers/tap them
-pay attacking requirements (if any)/handle triggers
-fast effects
3) Declare Blockers Step
-defending player decides on blockers
-active player determines combat damage assignment order for attackers
-defending player determines combat damage assignment order for blockers
-put triggers (like "When [this creature] blocks...") on the stack
-fast effects
4) Assign Combat Damage Step
-assign and deal combat damage
-put triggers (like "When [this creature] blocks...") on the stack
-fast effects
5) End of Combat Step
-all "at end of combat." abilities trigger and go on the stack
-fast effects
This is a simplified version of Comp Rules 506 and on. Even more simply:
-Begin Combat
-Do stuff
-Declare Attackers
-Do stuff
-Declare Blockers
-Do stuff
-Assign Damage
-Do stuff
-End Combat
If they have declared attackers, you declare no blockers, they can respond with a {Giant Growth} and you can't decide to block, if that's what you're getting at. You could however respond to the growth with an {Unsummon} before the Assign Damage step.
"Return target thread from the graveyard onto the battlefield."