
At the beginning of your upkeep, put a -1/-1 counter on this creature.
Whenever you cast a noncreature spell, remove a -1/-1 counter from this creature.
Illustrated by Yeong-Hao Han · Amonkhet Remastered · #165
2017-07-14
Magmaroth’s second ability resolves before the spell that caused it to trigger. The ability will resolve even if that spell is countered.