Eternal Taskmaster
Creature — Zombie
This creature enters tapped.
Whenever this creature attacks, you may pay 
. If you do, return target creature card from your graveyard to your hand.
"They are called Eternals. They will never stop." —Jace Beleren
Tomasz Jedruszek
Jumpstart (JMP)
• #228Rulings
You can't pay {2}{B} more than once each time Eternal Taskmaster's ability resolves.
(wotc • 2019-05-03)
Rulings
You can't pay {2}{B} more than once each time Eternal Taskmaster's ability resolves.
(wotc • 2019-05-03)