In a nutshell
- The power and toughness of creature are determined by applying these effects in order:
- p/t-setting abilities from the creature itself (characteristic-defining abilities)
- p/t-setting effects from other sources
- Effects that give +X/+Y or -X/-Y
- p/t-modifying counters
- Effects that switch power and toughness
- Within each sublayer, the effect that started first is applied first. Other effects are applied later in timestamp order.
- Equipment have a timestamp based on when they were attached to a creature. They need to actually move to a different creature to get a new timestamp.
Q: Amy casts a Tarmogoyf while all graveyards are empty. Then she casts Decree of Savagery. After that resolves, Nicole uses Omnibian‘s ability on Tarmogoyf, then responds by casting Auger Spree on it. In response to Auger Spree, Amy casts Strange Inversion on Tarmogoyf. What is Tarmogoyf’s p/t after everything on the stack resolves?
A: We parse each effect acting on Tarmogoyf’s p/t into its appropriate sublayer, then apply them in layer order. We have:
p/t-setting CDA – Tarmogoyf
Other p/t-setting effects – Omnibian
p/t buffs and debuffs – Auger Spree
Counters – Decree of Savagery’s +1/+1 counters
p/t-switching effects – Strange Inversion
So, Tarmogoyf starts as a 2/3 (Instant and Sorcery). Omnibian makes it a 3/3. Then, Auger Spree applies, making Tarmogoyf 7/-1. The +1/+1 counters from Decree of Savagery make it 11/3. Finally, Strange Inversion makes it a 3/11.
Note: The names of the cards involved are what give this section the name “TOADS”.
Note: Even though Tarmogoyf’s toughness was less than 1 after applying Auger Spree, it did not die there because state-based actions are not performed continuously, but rather only when a player would get priority and during the cleanup step. At no point during the process of casting all those spells did Tarmogoyf have 0 or less toughness.
Note: Suppose Amy had not cast Decree of Savagery. Tarmogoyf would then be a -1/7. It would deal 0 damage in combat or in a fight, but it would need to get +2/+0 to get up to 1 power.
Q: Can I fetch a Tarmogoyf with Imperial Recruiter?
A: Probably not. Tarmogoyf has a characteristic-defining ability that sets its power and toughness. Unlike most other types of abilities, CDA’s work everywhere, even when the object they’re on isn’t on the battlefield. Imperial Recruiter sees the same P/T for Tarmogoyf as it would have normally, so you can’t make this play unless there are two or fewer card types in all graveyards.
Note: There are CDA’s that define things other than P/T. Changeling and Ghostfire are good examples. If it sets a characteristic that would normally be found printed elsewhere on the card and isn’t conditional, it’s a CDA, and therefore applies everywhere. Examples of conditional effects include Possessed Nomad‘s color change, which depends on having threshold and Nyxathid‘s p/t debuff, which relies on having a chosen opponent. Those abilities would not function while the cards were off the battlefield. Further info on CDA’s can be found in my L2 prep material.