ConvokeConvoke is a static ability that functions while the spell with convoke is on the stack. “Convoke” means “For each colored mana in this spell’s total cost, you may tap an untapped creature of that color you control rather than pay that mana. For each generic mana in this spell’s total cost, you may tap an untapped creature you control rather than pay that mana.”
The convoke ability isn’t an additional or alternative cost and applies only after the total cost of the spell with convoke is determined.
A creature tapped to pay for mana in a spell’s total cost this way is said to have “convoked” that spell.
Multiple instances of convoke on the same spell are redundant. (CR 702.51) (Your creatures can help
castTo cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. A player may cast a spell if they have priority. See rule 601, “Casting Spells.”
To cast a card is to cast it as a spell. (CR 701.5) this spell. Each creature you
tapTo tap a permanent, turn it sideways from an upright position. Only untapped permanents can be tapped. (CR 701.26) while casting this spell pays for
or one mana of that creature's color.)
FlyingFlying is an evasion ability.
A creature with flying can’t be blocked except by creatures with flying and/or reach. A creature with flying can block a creature with or without flying. (See rule 509, “Declare Blockers Step,” and rule 702.17, “Reach.”)
Multiple instances of flying on the same creature are redundant. (CR 702.9)
DevourDevour is a static ability. “Devour N” means “As this object enters, you may sacrifice any number of creatures. This permanent enters with N +1/+1 counters on it for each creature sacrificed this way.”
Some objects have abilities that refer to the number of creatures the permanent devoured. “It devoured” means “sacrificed as a result of its devour ability as it entered the battlefield.”
Devour [quality] is a variant of devour. “Devour [quality] N” means “As this object enters, you may sacrifice any number of [quality] permanents. This permanent enters with N +1/+1 counters on it for each permanent sacrificed this way.” (CR 702.82) 2 (As this creature enters, you may
sacrificeTo sacrifice a permanent, its controller moves it from the battlefield directly to its owner’s graveyard. A player can’t sacrifice something that isn’t a permanent, or something that’s a permanent they don’t control. Sacrificing a permanent doesn’t destroy it, so regeneration or other effects that replace destruction can’t affect this action. (CR 701.21) any number of creatures. It enters with twice that many +1/+1
countersTo counter a spell or ability is to cancel it: remove it from the stack without resolving it. A counter on an object or player is instead a marker that changes characteristics or interacts with rules or abilities; for example, a +1/+1 counter modifies a creature’s power and toughness. (CR 701.6; 122.1) on it.)