I've played a few games and an effect happens that I do not understand:
- I declared an attacker
- Opponent declares a blocker
- I use Unsummon or other Instant such as Murder and remove the declared blocker
- Blocker is sent to graveyard
- Opponent takes no damage and my attacker remains tapped! How come my attacker didn't attack?
A similar effect that I don't understand happens in a slightly different scenario:
- I declare an attacker
- Opponent declares a blocker
- I cast an Instant that makes my attacker unblockable
- My attacker still clanks with blocker and trades damage! Why isn't the attack made unblockable?
What is this rule/effect called? Can someone help me understand it better?