Affectionate Indrik — ruling 1

You choose the target of the triggered ability as it goes on the stack, but you choose whether the creatures fight as that ability resolves.

Affectionate Indrik — ruling 2

If the target creature is an illegal target when Affectionate Indrik's ability tries to resolve, the ability doesn't resolve. If Affectionate Indrik is no longer on the battlefield, the target creature won't deal or be dealt damage.

Affectionate Indrik : règles, fonctionnement et interactions (MTG)

Affectionate Indrik 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

When this creature enters, you may have it fight target creature you don't control. (Each deals damage equal to its power to the other.)

How it works : Affectionate Indrik

Original English text — Wizards of the Coast / Scryfall

#1October 5, 2018· Wizards of the Coast
You choose the target of the triggered ability as it goes on the stack, but you choose whether the creatures fight as that ability resolves.
No other card is named in this ruling.
#2October 5, 2018· Wizards of the Coast
If the target creature is an illegal target when Affectionate Indrik's ability tries to resolve, the ability doesn't resolve. If Affectionate Indrik is no longer on the battlefield, the target creature won't deal or be dealt damage.
No other card is named in this ruling.