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)
RavenousRavenous is a keyword found on some creature cards with in their mana cost. Ravenous represents both a replacement effect and a triggered ability. “Ravenous” means “This permanent enters with X +1/+1 counters on it” and “When this permanent enters, if X is 5 or more, draw a card.” See rule 107.3m. (CR 702.156) (This creature enters with X +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. If X is 5 or more, draw a card when it enters.)
When this creature enters, target creature attacks target opponent this turn if able.