Notorious Rules Interactions

Sometimes the game needs facts about an object that has already left the zone. It uses Last Known Information — the object's characteristics as they last existed. Classic cases: a cost or effect like "Sacrifice a creature: add mana equal to its power" uses the sacrificed creature's last power; a "when this dies" ability looks back at how the creature last existed on the battlefield.

When multiple replacement (or prevention) effects would apply to the same event, the affected player — or the controller/owner of the affected object — chooses the order to apply them. Each can apply only once. This is how "enters with a counter," "enters tapped," and doubling effects like Doubling Season get sequenced: the affected object's controller decides.

If the game enters a mandatory loop that no player can stop and that involves no choices, the game is a draw. If a player has a choice within the loop, they must eventually make a different choice to break it — the game doesn't just end. Players may also propose shortcuts ("I do this 50 times"); an opponent can interrupt a shortcut at any point where they could have acted.

Two that catch people out:

• A land you've controlled continuously since the start of your most recent turn that becomes a creature can attack immediately — control, not "became a creature," drives summoning sickness.
• A copy effect (layer 1) copies printed/copiable values, not counters or other-layer effects; counters (7c) and modifiers (7d) then apply on top of the copy.