Splendid Agony — ruling 1

You choose how the counters will be distributed as you cast Splendid Agony. Each target creature must be assigned at least one counter.

Splendid Agony — ruling 2

If one of two target creatures becomes an illegal target in response to Splendid Agony, the -1/-1 counter that would have been put on that creature is lost. It can’t be put on the legal target.

Splendid Agony : règles, fonctionnement et interactions (MTG)

Splendid Agony 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

Distribute two -1/-1 counters among one or two target creatures.

How it works : Splendid Agony

Original English text — Wizards of the Coast / Scryfall

#1April 18, 2017· Wizards of the Coast
You choose how the counters will be distributed as you cast Splendid Agony. Each target creature must be assigned at least one counter.
No other card is named in this ruling.
#2April 18, 2017· Wizards of the Coast
If one of two target creatures becomes an illegal target in response to Splendid Agony, the -1/-1 counter that would have been put on that creature is lost. It can’t be put on the legal target.
No other card is named in this ruling.