If I play Overrun or Infest, THEN play a creature after the prior spell resolves, is that creature affected? I assume so, but is this ever not true?
Do spells that change power/toughness of all creatures until end of turn affect creatures played afterwards? [duplicate]
4This is a good question if you want a general explanation of how this works, but the specific question is directly answered by the sole ruling on Overrun: "Overrun affects only creatures you control at the time it resolves. It won't affect creatures that come under your control later in the turn."– CascabelDec 26, 2015 at 14:01
Uh...so....does that mean that's unique to Overrun, or it applies to all cards that say "creatures you control," or cards that say "creatures target player controls," or any cards that affect creatures without having a target?– temporary_user_nameDec 27, 2015 at 1:53
It means it applies to effects that change power and toughness. Nothing special about Overrun in that regard. I'll write a full answer soonish if no one else does.– CascabelDec 27, 2015 at 2:49
Actually, it turns out this is a duplicate! The accepted answer there is not terribly helpful, but the top voted one gives a full explanation.– CascabelDec 27, 2015 at 2:53
No, it will not be affected.
The answer varies based on what created the effect, and what the effect does. The following are the three cases:
A continuous effect generated by a static ability.
This is covered by 611.3a.
611.3a A continuous effect generated by a static ability isn’t “locked in”; it applies at any given moment to whatever its text indicates.
A continuous effect generated by something other than a static ability, and it modifies the characteristics of objects. (Characteristics are defined CR 109.3, included below.)
This is covered by the first half of 611.2c.
611.2c If a continuous effect generated by the resolution of a spell or ability modifies the characteristics or changes the controller of any objects, the set of objects it affects is determined when that continuous effect begins. After that point, the set won’t change. [...]
A continuous effect generated by something other than a static ability, and it doesn't modify the characteristics of objects.
This is covered by the second half of 611.2c.
611.2c [...] A continuous effect generated by the resolution of a spell or ability that doesn’t modify the characteristics or change the controller of any objects modifies the rules of the game, so it can affect objects that weren’t affected when that continuous effect began. [...]
For both Overrun and Infest, we're talking about a continuous effect generated by something other than a static ability, and it modifies the characteristics of objects. As such, only the permanents that were creatures when the spell resolved are affected by the spell.
109.3. An object’s characteristics are name, mana cost, color, color indicator, card type, subtype, supertype, rules text, abilities, power, toughness, loyalty, hand modifier, and life modifier. Objects can have some or all of these characteristics. Any other information about an object isn’t a characteristic. For example, characteristics don’t include whether a permanent is tapped, a spell’s target, an object’s owner or controller, what an Aura enchants, and so on