Advanced Rules: Layers & Replacement Effects

When multiple continuous effects modify the same objects, the game needs a consistent order to apply them so everyone gets the same result. That order is the layer system (CR 613). You apply effects layer by layer, in this order:

1. Copy effects
2. Control-changing effects
3. Text-changing effects
4. Type-changing effects
5. Color-changing effects
6. Ability add/remove effects
7. Power/Toughness-changing effects

Layer 7 has its own internal order, which trips people up constantly:

1. 7a — characteristic-defining abilities that set P/T (e.g. "*/* equal to...").
2. 7b — effects that set P/T to a specific value (e.g. "becomes 1/1").
3. 7c — P/T changes from counters (+1/+1, −1/−1).
4. 7d — effects that modify P/T without setting it (e.g. "+2/+2 until end of turn," anthems).
5. 7e — effects that switch power and toughness.

Because counters (7c) apply after "becomes 1/1" (7b), a 5/5 that "becomes 1/1" and has a +1/+1 counter ends up 2/2.

Within a single layer, effects normally apply in timestamp order (oldest first). The exception is dependency: if applying effect A would change what effect B does or applies to, B waits and applies after A, regardless of timestamps. Dependency is checked within a layer; if a loop would form, timestamps break it.

Replacement effects ("if... would..., instead...") watch for an event and modify it as it happens. They do not use the stack and can't be responded to. Rules:

• Each replacement effect can apply only once to a given event.
• If several apply to the same event, the affected object's controller (or its owner, or the affected player) chooses the order to apply them.
• Prevention effects ("prevent the next N damage") are a kind of replacement effect and interact the same way.