Rosheen, Roaring Prophet — ruling 1

You can spend mana generated with Rosheen's last ability on any part of a cost that contains {X}. You're not limited to spending it only on the {X} part.

Rosheen, Roaring Prophet — ruling 2

You don't have to spend all of the mana generated with Rosheen's last ability on the same cost.

Rosheen, Roaring Prophet — ruling 3

You can use the mana generated with Rosheen's last ability in any cost you pay that includes {X}, including the mana costs of spells, activation costs, and even costs for special actions (such as morph). Any time you pay mana, that's a cost.

Rosheen, Roaring Prophet — ruling 4

A "cost that contains {X}" may be a spell's total cost, an activated ability's cost, a suspend cost, or a cost you're asked to pay as part of the resolution of a spell or ability (such as Condescend). A spell's total cost includes either its mana cost (printed in the upper right corner) or its alternative cost (such as flashback), as well as any additional costs (such as kicker). If it's something you can spend mana on, it's a cost. If that cost includes the {X} symbol in it, you can spend mana generated by Rosheen on that cost.

Rosheen, Roaring Prophet : règles, fonctionnement et interactions (MTG)

Rosheen, Roaring Prophet 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

When Rosheen enters, mill six cards. You may put a card with in its mana cost from among them into your hand. : Reveal any number of cards with in their mana cost in your hand. Add for each card revealed this way. Spend this mana only on costs that contain .

How it works : Rosheen, Roaring Prophet

Original English text — Wizards of the Coast / Scryfall

#1June 7, 2024· Wizards of the Coast
You can spend mana generated with Rosheen's last ability on any part of a cost that contains . You're not limited to spending it only on the part.
No other card is named in this ruling.
#2June 7, 2024· Wizards of the Coast
You don't have to spend all of the mana generated with Rosheen's last ability on the same cost.
No other card is named in this ruling.
#3June 7, 2024· Wizards of the Coast
You can use the mana generated with Rosheen's last ability in any cost you pay that includes , including the mana costs of spells, activation costs, and even costs for special actions (such as morph). Any time you pay mana, that's a cost.
No other card is named in this ruling.
#4June 7, 2024· Wizards of the Coast
A "cost that contains " may be a spell's total cost, an activated ability's cost, a suspend cost, or a cost you're asked to pay as part of the resolution of a spell or ability (such as Condescend). A spell's total cost includes either its mana cost (printed in the upper right corner) or its alternative cost (such as flashback), as well as any additional costs (such as kicker). If it's something you can spend mana on, it's a cost. If that cost includes the symbol in it, you can spend mana generated by Rosheen on that cost.
No other card is named in this ruling.