Ratchet Bomb — ruling 1

Tokens that aren't a copy of something else don't have a mana cost. Anything without a mana cost normally has a mana value of 0.

Ratchet Bomb — ruling 2

If a permanent has {X} in its mana cost, X is considered to be 0.

Ratchet Bomb : règles, fonctionnement et interactions (MTG)

Ratchet Bomb 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

: Put a charge counter on this artifact. , Sacrifice this artifact: Destroy each nonland permanent with mana value equal to the number of charge counters on this artifact.

How it works : Ratchet Bomb

Original English text — Wizards of the Coast / Scryfall

#1August 7, 2020· Wizards of the Coast
Tokens that aren't a copy of something else don't have a mana cost. Anything without a mana cost normally has a mana value of 0.
No other card is named in this ruling.
#2August 7, 2020· Wizards of the Coast
If a permanent has in its mana cost, X is considered to be 0.
No other card is named in this ruling.