A-Radha's Firebrand

Whenever Radha's Firebrand attacks, target creature defending player controls with power less than or equal to Radha's Firebrand's power can't block this turn.
Domain — {5}{R}: Radha's Firebrand gets +2/+2 until end of turn. This ability costs {1} less to activate for each basic land type among lands you control. Activate only once each turn.