Magic Missile — ruling 1

You divide the damage as you cast Magic Missile. Each target must be assigned at least 1 damage.

Magic Missile — ruling 2

If Magic Missile has one or more targets, and some (but not all) of them are illegal as Magic Missile tries to resolve, the amount of damage dealt to the remaining legal targets doesn't change. If all targets become illegal, Magic Missile won't resolve.

Magic Missile : règles, fonctionnement et interactions (MTG)

Magic Missile 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

This spell can't be countered. Magic Missile deals 3 damage divided as you choose among one, two, or three targets.

How it works : Magic Missile

Original English text — Wizards of the Coast / Scryfall

#1July 23, 2021· Wizards of the Coast
You divide the damage as you cast Magic Missile. Each target must be assigned at least 1 damage.
No other card is named in this ruling.
#2July 23, 2021· Wizards of the Coast
If Magic Missile has one or more targets, and some (but not all) of them are illegal as Magic Missile tries to resolve, the amount of damage dealt to the remaining legal targets doesn't change. If all targets become illegal, Magic Missile won't resolve.
No other card is named in this ruling.