Pursued Whale
Creature — Whale
When this creature enters, each opponent creates a 1/1 red Pirate creature token with "This token can't block" and "Creatures you control attack each combat if able."
Spells your opponents cast that target this creature cost 
more to cast.
Jonathan Kuo
Rulings
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases (such as that of Pursued Whale), then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.
(wotc • 2020-06-23)
If a creature affected by the Pirate token 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 it attack, the player isn't forced to pay that cost, so it doesn't have to attack in that case either.
(wotc • 2020-06-23)
Printings
Rulings
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases (such as that of Pursued Whale), then apply any cost reductions. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.
(wotc • 2020-06-23)
If a creature affected by the Pirate token 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 it attack, the player isn't forced to pay that cost, so it doesn't have to attack in that case either.
(wotc • 2020-06-23)