Yukai, Blade of the Void

Cannot be blocked by more than one creature.
Whenever this creature becomes blocked, you
may pay {1} or {1}{u}{b}, then choose one:
•Target creature blocking this card gets -2/-1
until end of turn.
•Yukai, Blade of the Void gets +2/+1
until end of turn.
If you paid {1}{u}{b}, you may choose both
and Yukai, Blade of the Void gains First Strike
and Vigilance until your next upkeep.