118.9. Some spells have alternative costs. An alternative cost is a cost listed in a spell's text, or applied to it from another effect, that its controller may pay rather than paying the spell's mana cost. Alternative costs are usually phrased, "You may [action] rather than pay [this object's] mana cost," or "You may cast [this object] without paying its mana cost." Note that some alternative costs are listed in keywords; see rule 702.
118.9a. Only one alternative cost can be applied to any one spell as it's being cast. The controller of the spell announces their intentions to pay that cost as described in rule 601.2b.
Quote from ilovesaprolings »If i have Sek'kuar, deathkeeper and 3 creatures on the board and i play bloodspore thrinax. devouring the 3 creatures, will the 3 graveborn tokens that i make with Sek'kuar enter with 3 +1/+1 counters?
Quote from Jsun »If my opponent has no cards in hand and I cast Nezumi Shortfang, does Nezumi automatically flip or do I have to pay to make Nezumi flip?
721.2e. If a merged permanent contains face-up and face-down components, the permanent's status is determined by its topmost component. If a face-down permanent becomes a face-up permanent as a result of an object merging with it, other effects don't count it as being turned face up.
Quote from dbengio »If Dark Impostor has 2 counters on it and the opponent casts Giant Killer does it kill it because it has power 4 or it doesn't because it has power 2 and 2 counters on it?
Quote from dbengio »Does deathtouch kill plans walkers?
Quote from Jeff CH »Synod Sanctum basic question...
When this card says: remove target permament YOU CONTROL from the game. Do i control a permanent if its in my hand, in play or in my graveyard?
Quote from Tommyygguunn »Then with Kokushos ability I’d lose 5 but then gain 10 from my 2 other opponents losing 5 life each due to his trigger?
Quote from Squirrel455 »Can I use walking desecration to have a creature with shroud attack? Does this ability count as an area effect?