If I attack into an Overzealous Fan with an Irresistable Faefolk planning to use an Ambush unit, does Overzealous have to decide whether it'll kill itself on defend to move Fae Folk back before I react with Ambush?

Question

Accepted Answer

To clarify the interaction between **Overzealous Fan**, **Irresistible Faefolk**, and an **Ambush** unit, we must follow the updated *Unleashed* rules, specifically regarding when costs are paid for triggered abilities.

### The Ruling
**Yes, the player controlling Overzealous Fan must decide whether or not to trigger its ability—and pay the cost of killing it—at the moment the ability triggers.**

Under the current rules (clarified by **RiftJudge FAQ #8702** and **#9611**), the "kill me" instruction on **Overzealous Fan** is a "cost within instruction." Because the ability uses the "you may" template, the controller must choose whether to use the ability when the trigger condition is met (when the unit gains the Defender designation). If they choose to use it, they must pay the cost—killing the **Overzealous Fan**—upfront to place the ability on the chain.

### Sequence of Events
1.  **Combat Begins:** You move **Irresistible Faefolk** to an unoccupied battlefield. This applies "Contested" status, making you the **Attacker**.
2.  **Faefolk Trigger:** **Irresistible Faefolk's** "When I move..." ability triggers, goes on the chain, and resolves, moving an enemy unit (or the **Overzealous Fan**) to the battlefield.
3.  **Defender Designation:** The unit (e.g., **Overzealous Fan**) gains the "Defender" designation. This triggers its "When I defend" ability.
4.  **The Decision (Upfront):** The controller of **Overzealous Fan** must immediately decide:
    *   **If they decline:** They do not kill the Fan, the ability never goes on the chain, and the game proceeds.
    *   **If they accept:** They must immediately kill the **Overzealous Fan** (paying the cost). Only then is the ability placed on the chain as a pending item, and a target (the attacking unit) must be selected.
5.  **Reaction:** Only *after* the ability is placed on the chain (and the Fan is already in the trash) can you play your **Ambush** unit as a [Reaction].

### Summary
*   **Timing:** You cannot "wait" to see if the opponent plays an Ambush unit before deciding to kill the Fan. The Fan's controller must commit to paying the cost to put the trigger on the chain immediately upon gaining the Defender designation.
*   **Contradiction Note:** Please be aware that while older community FAQs (such as #270) suggested the decision happened at resolution, those have been superseded by the *Unleashed* update rules and **RiftJudge FAQ #8702**, which explicitly clarifies that "kill me" is a cost paid upfront. The sequence in this answer reflects the current official ruling.