Roar of Endless Song — ruling 1

If an effect instructs you to “double” a creature’s power, that creature gets +X/+0, where X is its power as that effect begins to apply. Similarly, a creature whose toughness is doubled gets +0/+X, where X is its toughness as the effect begins to apply.

Roar of Endless Song : règles, fonctionnement et interactions (MTG)

Roar of Endless Song 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

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I, II — Create a 5/5 green Elephant creature token. III — Double the power and toughness of each creature you control until end of turn.

How it works : Roar of Endless Song

Original English text — Wizards of the Coast / Scryfall

#1April 4, 2025· Wizards of the Coast
If an effect instructs you to “double” a creature’s power, that creature gets +X/+0, where X is its power as that effect begins to apply. Similarly, a creature whose toughness is doubled gets +0/+X, where X is its toughness as the effect begins to apply.
No other card is named in this ruling.