Angelic Purge + Demonic Pact

[Mattao19]

I have a {Demonic Pact} out and I've chosen all but lose the game. Nothing else is on the board. Can I cast {Angelic Purge} targeting my pact (only target) while also saccing the same pact?

[Prplprince]

I don't believe so because it is an additional cost to cast which means it will not be a valid target once targets are selected.

[Mattao19]

Lol hasn't happened yet so good to know lol thanks

[Nymuera]

I believe this is legal. It will take me a bit to quote the rules. Targets are chosen before costs are paid. The spell will go on the stack targeting the enchantment. Sack the enchantment and pay the mana. No more target so spell fizzles, but enchantment is still gone.

[Nymuera]

601.2.: To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. Casting a spell includes proposal of the spell (rules 601.2a–d) and determination and payment of costs (rules 601.2f–h). To cast a spell, a player follows the steps listed below, in order. A player must be legally allowed to cast the spell to begin this process, ignoring any effect that would prohibit that spell from being cast based on information determined during that spell's proposal. (Such effects are considered during the check detailed in rule 601.2e.) If, at any point during the casting of a spell, a player is unable to comply with any of the steps listed below, the casting of the spell is illegal; the game returns to the moment before the casting of that spell was proposed (see rule 717, "Handling Illegal Actions").

[Nymuera]

601.2a: To propose the casting of a spell, a player first moves that card (or that copy of a card) from where it is to the stack. It becomes the topmost object on the stack. It has all the characteristics of the card (or the copy of a card) associated with it, and that player becomes its controller. The spell remains on the stack until it's countered, it resolves, or an effect moves it elsewhere.

[Nymuera]

601.2c: The player announces his or her choice of an appropriate player, object, or zone for each target the spell requires. A spell may require some targets only if an alternative or additional cost (such as a buyback or kicker cost), or a particular mode, was chosen for it; otherwise, the spell is cast as though it did not require those targets. If the spell has a variable number of targets, the player announces how many targets he or she will choose before he or she announces those targets. In some cases, the number of targets will be defined by the spell's text. Once the number of targets the spell has is determined, that number doesn't change, even if the information used to determine the number of targets does. The same target can't be chosen multiple times for any one instance of the word "target" on the spell. However, if the spell uses the word "target" in multiple places, the same object, player, or zone can be chosen once for each instance of the word "target" (as long as it fits the targeting criteria). If any effects say that an object or player must be chosen as a target, the player chooses targets so that he or she obeys the maximum possible number of such effects without violating any rules or effects that say that an object or player can't be chosen as a target. The chosen players, objects, and/or zones each become a target of that spell. (Any abilities that trigger when those players, objects, and/or zones become the target of a spell trigger at this point; they'll wait to be put on the stack until the spell has finished being cast.)
Example: If a spell says "Tap two target creatures," then the same creature can't be chosen twice; the spell requires two different legal targets. A spell that says "Destroy target artifact and target land," however, can target the same artifact land twice because it uses the word "target" in multiple places.

[Nymuera]

601.2e: The game checks to see if the proposed spell can legally be cast. If the proposed spell is illegal, the game returns to the moment before the casting of that spell was proposed (see rule 717, "Handling Illegal Actions").

[Nymuera]

601.2f: The player determines the total cost of the spell. Usually this is just the mana cost. Some spells have additional or alternative costs. Some effects may increase or reduce the cost to pay, or may provide other alternative costs. Costs may include paying mana, tapping permanents, sacrificing permanents, discarding cards, and so on. The total cost is the mana cost or alternative cost (as determined in rule 601.2b), plus all additional costs and cost increases, and minus all cost reductions. If multiple cost reductions apply, the player may apply them in any order. If the mana component of the total cost is reduced to nothing by cost reduction effects, it is considered to be {0}. It can't be reduced to less than {0}. Once the total cost is determined, any effects that directly affect the total cost are applied. Then the resulting total cost becomes "locked in." If effects would change the total cost after this time, they have no effect.

[Mr_Fahrenheit]

Almost.

I believe it is actually

- Announce your intention to play the purge
- Place purge on the stack
- Announce the pact as the target
- Pay costs (including sacrificing the pact)
- Opponent gets priority.
- If nothing else goes on the stack the purge fizzles
- Purge goes to graveyard.
- Active player gets priority again with an empty stack

[Remillo]

Almost.

I believe it is actually

- Announce your intention to play the purge
- Place purge on the stack
- Announce the pact as the target
- Pay costs (including sacrificing the pact)
- Opponent gets priority.
- If nothing else goes on the stack the purge fizzles
- Purge goes to graveyard.
- Active player gets priority again with an empty stack

This is correct.  Because targets are chosen before costs are calculated and payed (because things like {Elderwood Scion} or {Monastery Siege} will make it more expensive when it's calculated), you can almost always sacrifice what you're deciding to target.  I sometimes loop Bojuka Bog using Dust Bowl by targeting the Bog and Sacing it if my opponent has no non-basics.

[Mattao19]

So just so I'm clear. It's a legal play to target pact and sac the same pact as part of the cost?

[redwolv]

Yup! Pruge that pact