Flash

When Idol of the Deep King enters the battlefield, it deals 2 damage to any target.

Craft with artifact (, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Enchant creature

When Knightly Valor enters the battlefield, create a 2/2 white Knight creature token with vigilance. (Attacking doesn't cause it to tap.)

Enchanted creature gets +2/+2 and has vigilance.

Whenever one or more creatures you control deal combat damage to a player, tap all lands that player controls and untap all lands you control.

Landfall — Whenever a land enters the battlefield under your control, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Sunken Citadel enters the battlefield tapped. As it enters, choose a color.

: Add one mana of the chosen color.

: Add two mana of the chosen color. Spend this mana only to activate abilities of land sources.

Waterfront District enters the battlefield tapped.

: Add or .

, , Sacrifice Waterfront District: Draw a card.