Serum Sovereign — ruling 1

Removing an oil counter is part of the cost to activate Serum Sovereign's last ability. Players can't respond with a spell or ability that removes counters to prevent you from drawing a card and scrying 2.

Serum Sovereign : règles, fonctionnement et interactions (MTG)

Serum Sovereign 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

Flying Whenever you cast a noncreature spell, put an oil counter on this creature. , Remove an oil counter from this creature: Draw a card, then scry 2.

How it works : Serum Sovereign

Original English text — Wizards of the Coast / Scryfall

#1February 4, 2023· Wizards of the Coast
Removing an oil counter is part of the cost to activate Serum Sovereign's last ability. Players can't respond with a spell or ability that removes counters to prevent you from drawing a card and scrying 2.
No other card is named in this ruling.