Hatrei, The Midnight Star

Trample, Extort Whenever you cast a spell you
may pay {x}. If you do, each opponent loses {x} life
and you gain {x} life.)
Add {x} +1 +1 counters
Whenever Hatrei, The Midnight Star attacks
choose one creature and give it Extort.
( If a creature has multiple instances of extort, each triggers separately.)