Yuna's WhistleHow it works & interactions with other cards

What It Does

Yuna's Whistle is a 'tutor' style effect that digs through your library for the first creature card it finds. It doesn't just put that card in your hand; it also generates a delayed triggered ability based on the creature's mana value. This allows you to bolster a creature already on the battlefield with +1/+1 counters equal to the cost of the card you just found.

How It Resolves Step by Step

First, you cast Yuna's Whistle. Unlike many spells, you do not choose a target when you cast it. Upon resolution, you reveal cards from the top of your library one by one until a creature card appears. That card goes to your hand, and the others go to the bottom of your library randomly. Immediately after, a reflexive triggered ability goes on the stack. Now, you choose a target creature you control to receive the +1/+1 counters. Players can respond to this new trigger before any counters are placed.

Common Mistakes

A frequent error is trying to target a creature while casting the spell. Because the target is chosen by a reflexive trigger, you wait until the creature is revealed to pick your target. Additionally, remember that if you reveal a creature with {X} in its mana cost, that X is always treated as 0 when calculating how many +1/+1 counters are distributed.

When to Play It

Use Yuna's Whistle at the end of your opponent's turn to find a threat for your next move, or cast it during your combat step to surprise an opponent with an unexpected stat boost. Because it is an instant, it is perfect for baiting out removal spells or forcing unfavorable blocks.

Interaction examples

Protecting the Targeted Prize

Heroic Intervention

You resolve Yuna's Whistle and reveal a high-cost creature. The reflexive trigger goes on the stack targeting your 2/2 creature. In response, your opponent tries to destroy your creature. You can cast Heroic Intervention to give your creature hexproof. Heroic Intervention resolves first, then the Whistle's trigger resolves, successfully placing the +1/+1 counters on your protected creature.

The Beast Within Response

Beast Within

You cast Yuna's Whistle. While the spell is resolving, you reveal a creature. The reflexive trigger targets your favorite Elf. Your opponent responds by casting Beast Within on that Elf. Beast Within resolves, destroying the Elf and giving you a 3/3 Beast token. When the Whistle's trigger finally tries to resolve, its original target is gone. The ability fizzles, and no counters are placed on the new Beast token because targets cannot be changed at that point.