Magmaroth — ruling 1

Magmaroth’s second ability resolves before the spell that caused it to trigger. The ability will resolve even if that spell is countered.

Magmaroth : règles, fonctionnement et interactions (MTG)

Magmaroth is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

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.

How it works : Magmaroth

Original English text — Wizards of the Coast / Scryfall

#1July 14, 2017· Wizards of the Coast
Magmaroth’s second ability resolves before the spell that caused it to trigger. The ability will resolve even if that spell is countered.
No other card is named in this ruling.