Replacement Effects

Effects that change how an event happens instead of reacting to it.

The rules are CR 614 (replacement), 615 (prevention) and 616 (what happens when several apply at once — the choose-one-then-repeat process).

A replacement effect watches for an event that would happen and replaces it with a different one. It doesn't react to the event — it changes it, before it ever occurs. The rules describe these effects as shields around whatever they protect, and that's the right picture.

Spotting one

"Instead" is the classic marker: the event that would have happened doesn't, and something else takes its place. "Skip" is the other one — skipping something is just "instead of doing it, do nothing".

Also replacement effects, despite not printing the word: "[This permanent] enters tapped", "enters with a +1/+1 counter", "as this enters, choose…", and regeneration (where "instead" is implicit in the definition).

Replacement effects never use the stack. The spell or ability that creates one can be countered before it resolves, but once the shield exists it just applies. There is nothing to respond to.

Three rules that shape everything

They must exist before the event. A replacement or prevention effect can't go back in time and change something that has already happened. Set up your prevention shield in response to the spell, not after it resolves.

Each one gets exactly one opportunity. A replacement effect doesn't invoke itself repeatedly — it gets a single chance to affect an event, or any modified events that replaced it. Without this, two effects that each replace the other's output would loop forever.

If an event is replaced, it never happened. A modified event happens instead, and that modified event is what abilities get to see. So if "if a creature would die, exile it instead" is in play, your creature has not died — "dies" means being put into a graveyard from the battlefield, and it never went there. Nothing that triggers on dying triggers. Leaves-the-battlefield abilities do still trigger, because leaving the battlefield genuinely happened.

And if the event a replacement effect was waiting for never occurs at all, the effect simply does nothing. No substitution, no consolation prize.

Who chooses when several apply

This is the rule people get backwards. When two or more replacement or prevention effects want to modify the same event, the affected object's controller chooses which to apply — or its owner if it has no controller, or the affected player if it's a player being affected.

Whose effects they are is irrelevant. Your opponent's shield and your own shield both applying to your creature? You choose.

Then, once one has been applied, the process repeats over whatever is still applicable, so the chooser may get several decisions in a row.

The choice isn't entirely free, though — there's a strict cascade of categories that must be taken first if present:

1. Self-replacement effects (a resolving spell replacing part of its own effect).
2. Effects changing under whose control an object enters.
3. Effects making an object enter as a copy.
4. Effects making a card enter with its back face up.
5. Anything else — now it's a free choice.

Regeneration, precisely

Regeneration is a destruction-replacement effect. "Regenerate [permanent]" means: the next time it would be destroyed, instead tap it, remove all damage from it, and remove it from combat.

Which tells you exactly what it does and doesn't stop. It saves a creature from lethal damage (destruction). It does nothing about 0 toughness (a put-into-graveyard, not a destruction), nothing about sacrifice, and nothing about exile.

Entering the battlefield

Effects that modify how a permanent enters are replacement effects, which means the permanent arrives already modified. A creature with "enters with two +1/+1 counters" is never on the battlefield without them — there is no intervening moment, nothing can be done in between, and anything watching for a creature entering with counters sees them immediately.

"Can't" is not a replacement effect

An effect saying something can't happen isn't technically a replacement effect, though it follows similar rules. The practical difference is that "can't" wins outright: where replacement effects participate in the choose-one-then-repeat process, a prohibition simply stops the event. There's nothing left to order.

25 questions in this track, checked against the 2026-06-19 Comprehensive Rules.

Rules covered: 405.6b, 500.11, 603.6b, 603.6c, 613.11, 614.1, 614.1a, 614.1b, 614.1c, 614.4, 614.5, 614.6, 614.7, 614.8, 614.10, 614.12, 614.15, 614.17, 615.1, 616.1, 616.1a, 616.1b, 616.1c, 616.1d, 616.1e, 616.1f, 700.4, 701.15, 701.15a, 702.15b.