Simian Grunts

Flash 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.

Echo is a triggered ability. “Echo [cost]” means “At the beginning of your upkeep, if this permanent came under your control since the beginning of your last upkeep, sacrifice it unless you pay [cost].”

Urza block cards with the echo ability were printed without an echo cost. These cards have been given errata in the Oracle card reference; each one now has an echo cost equal to its mana cost.