Royal Decree (TP4-001) [Tournament Pack 4] DP46 or leaves the field because

or leaves the field because of an opponent's card effect while its owner controls it: You can inflict 500 damage to your opponent for each "Frightfur" monster in your Graveyard

but it cannot attack

Set: Commander 2013 Type: Legendary Creature — Giant Soldier Rarity: Mythic Cost: {3}{W}{U}{B} At the beginning of your upkeep

Set: Kaladesh Inventions Type: Artifact Rarity: Mythic Cost: {1} {3}

Set: Portal Three Kingdoms Type: Legendary Creature — Human Rarity: Rare Cost: {1}{G}{G} {T}: Put target creature card from your graveyard on top of your library

Royal Decree (TP4-001) [Tournament Pack 4] DP46 or leaves the field becauseSet: Tournament Pack 4 Card type: Continuous Trap Rarity: Ultra Rare Attack: 0 Defense: 0 As long as this card remains face up on the field, negate the effects of all Trap Cards except this card on the field.