true believer/tendrils

[BigMac]

True Believer
WW
2/2
You can't be the target of spells or abilities.

The situation is you have an Aetervile untapped on the board with two counters on it. You have true believer in your hand. Your opponent is going wild on his storm combo and playes tendrils of agony. Can you still activate aethervile to get true believer on the board so you cannot be targetted anymore and tendrils needs to target himself.

Or should i wait till like spell 7 or 8 and then in reaction to a spell activate aethervile to get true believer on the table.

I am just wondering if you choose a target for the tendrils upon playing or upon resolution.

[Harlequin]

To answer the question you asked.  You choose the target of the intial CARD Tendrils of Agony, then a Storm trigger goes on the stack.  The way I think of a storm trigger is a bit like a .zip file.  It is one single trigger.  when that trigger resolves, you unpack N copies of Tendrils onto the stack.  Durring the resolution of the storm trigger, each copy get a target assigned.  So if you simply want to avoid being targeted by the copies you can drop the true beleiver when you get pirority with the Storm trigger on the stack. 

To answer the question you didn't ask:  It doesn't matter.  If a spell or ability's target has become illegal (or changed zones) then the spell "Fizzles" when it goes to resolve.  The technical term is 'countered apon resolution.'  The point is, True Beleiver will cause any copies of tendrils that are infact on the stack to NOT resolve even if they are already targeting you.  So I tendrils you for 50, you can let the storm trigger resolve, let me declare all my tendrils target you, THEN play your Believer and now when my copies go to resolve, they are countered apon resolution with no legal targets.

[Godder]

Targets of spells and abilities are almost always chosen on announcement of said spell/ability. In the case of Storm, that's when the trigger resolves and the copies are placed on the stack, so Aether Vial -> True Believer after the copies are on the stack, but before they resolve, would cause the copies to be countered on resolution (fizzle). Sacrificing Rector -> Ivory Mask would also work.

[Gabethebabe]

I would like to add that if you plop down True Believer with the Storm trigger on the stack, at the moment that Tendrils copies are put on the stack you MAY choose other targets. You´re not obliged to do so and you can therefore keep the original (albeit illegal) target.

With Tendrils this doesn´t really make a difference, if the caster targets himself he wins and lose twos life, but with Brain Freeze this is an essential difference.