Every Last Vestige Shall Rot — ruling 1

You choose the target player when the ability triggers. As the ability resolves, you choose a value for X and decide whether to pay {X}. If you do decide to pay {X}, it’s too late for any player to respond since the ability is already in the midst of resolving.

Every Last Vestige Shall Rot : règles, fonctionnement et interactions (MTG)

Every Last Vestige Shall Rot 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 you set this scheme in motion, you may pay . If you do, put each nonland permanent target player controls with mana value X or less on the bottom of its owner's library.

How it works : Every Last Vestige Shall Rot

Original English text — Wizards of the Coast / Scryfall

#1June 15, 2010· Wizards of the Coast
You choose the target player when the ability triggers. As the ability resolves, you choose a value for X and decide whether to pay . If you do decide to pay , it’s too late for any player to respond since the ability is already in the midst of resolving.
No other card is named in this ruling.