Baird, Steward of Argive

Text:

Vigilance
Creatures can't attack you or a planeswalker you control unless their controller pays for each of those creatures.

Rulings:

• 4/27/2018 If you control Baird, your opponents can choose not to pay to attack with a creature that attacks “if able.” If there’s no other player or planeswalker to attack, that creature simply doesn’t attack.
• 4/27/2018 In a Two-Headed Giant game, creatures can attack your teammate and planeswalkers your teammate controls without requiring a mana payment. This is a change from previous rules.