Forbidding Spirit
Creature — Spirit Cleric
When this creature enters, until your next turn, creatures can't attack you or planeswalkers you control unless their controller pays 
for each of those creatures.
"You will respect the dead."
Ryan Yee
Rulings
While Forbidding Spirit’s effect is in effect, 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.
(wotc • 2019-01-25)
Because it doesn’t modify the characteristics of creatures, Forbidding Spirit’s triggered ability can affect creatures that enter the battlefield after that ability resolves.
(wotc • 2019-01-25)
In a Two-Headed Giant game, creatures can attack your teammate and planeswalkers your teammate controls without requiring a mana payment.
(wotc • 2019-01-25)
Forbidding Spirit’s effect continues until your next turn even if Forbidding Spirit leaves the battlefield before then.
(wotc • 2019-01-25)
Rulings
While Forbidding Spirit’s effect is in effect, 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.
(wotc • 2019-01-25)
Because it doesn’t modify the characteristics of creatures, Forbidding Spirit’s triggered ability can affect creatures that enter the battlefield after that ability resolves.
(wotc • 2019-01-25)
In a Two-Headed Giant game, creatures can attack your teammate and planeswalkers your teammate controls without requiring a mana payment.
(wotc • 2019-01-25)
Forbidding Spirit’s effect continues until your next turn even if Forbidding Spirit leaves the battlefield before then.
(wotc • 2019-01-25)