Death Mutation — ruling 1

If the target is illegal on resolution, the entire spell doesn’t resolve. As such, you will not put any tokens onto the battlefield.

Death Mutation : règles, fonctionnement et interactions (MTG)

Death Mutation 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

Destroy target nonblack creature. It can't be regenerated. Create X 1/1 green Saproling creature tokens, where X is that creature's mana value.

How it works : Death Mutation

Original English text — Wizards of the Coast / Scryfall

#1August 1, 2008· Wizards of the Coast
If the target is illegal on resolution, the entire spell doesn’t resolve. As such, you will not put any tokens onto the battlefield.
No other card is named in this ruling.