Your local MTG noob... thx in advance

Question

ok, when its my opponents turn and they attack me and i have a fire wall out that lets me pay one red mana to give it 1/ 0 can i use that ability AFTER they say they are going to attack me and possibly kill their attacking creature. or do i have to use the ability before they attack and let them know that the wall is going to have X amount of damage??

Answer 1

Your opponent declares attackers.  He already know you can block with the wall and you can pump the wall with your mana, so if he's attacking, he already knows what he is possilby up against.  You first of all declare blockers and before damage is dealt, you pump the wall all you want/can, then damage is dealt.  So in answer to your question, you can wait until AFTER they say they are going to attack you.  That's what instant abilities are all about.

Answer 2

Before

Answer 3

THE CHOIE IS YOURS,

if it works for you, you can pump the wall and waive your finger saying if you attack, kaposssshhhhyour creatue dies here...JAJAJAJA MUA JA...

or just be like, oh he attacked wath ever will i do...? and then kaposshhhh declare a blocker and pump it up and be like jjijijijijijijijij.....

your oponent must be aware of what your creatures can do as well as you.\

ofcourse for every action they are entiteled to react and so on

he attacks

you block

(before damage is asigned) you pump up the wall

he can then cast an instant or use a creature ability

and then the satck is resolved

so in a way you still have to let him know before dammage is asigned but not before he has comited the creature to attack.

hope this helps