The wills of mortals shift as the tide ebbs and flows.

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Only Kiora would dare steal the weapon of a god. Only Kiora could have succeeded.

Bloomburrow Commander

Modern Horizons 3 Commander

The Lost Caverns of Ixalan Commander

Starter Commander Decks

The Brothers' War Commander

If a creature can't attack for any reason (such as being tapped or having come under that player's control that turn), then it doesn't attack. If there's a cost associated with having a creature attack, the player isn't forced to pay that cost, so it doesn't have to attack in that case either.

The controller of each attacking creature still chooses which player or planeswalker that creature attacks.