Mystic Genesis — ruling 1

If the target spell is an illegal target when Mystic Genesis tries to resolve, Mystic Genesis won’t resolve and none of its effects will happen. You won’t get an Ooze token.

Mystic Genesis — ruling 2

You may target a spell that can’t be countered. When Mystic Genesis resolves, the target spell will be unaffected, but you’ll still get an Ooze token.

Mystic Genesis : règles, fonctionnement et interactions (MTG)

Mystic Genesis 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

Counter target spell. Create an X/X green Ooze creature token, where X is that spell's mana value.

How it works : Mystic Genesis

Original English text — Wizards of the Coast / Scryfall

#1March 14, 2017· Wizards of the Coast
If the target spell is an illegal target when Mystic Genesis tries to resolve, Mystic Genesis won’t resolve and none of its effects will happen. You won’t get an Ooze token.
Card named in this ruling
Ooze
#2March 14, 2017· Wizards of the Coast
You may target a spell that can’t be countered. When Mystic Genesis resolves, the target spell will be unaffected, but you’ll still get an Ooze token.
Card named in this ruling
Ooze