FlashFlash is a static ability that functions in any zone from which you could play the card it’s on. “Flash” means “You may play this card any time you could cast an instant.”
Multiple instances of flash on the same object are redundant. (CR 702.8)
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) 1 (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 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.)