Affectionate Indrik

• WOTC Official Reminder Textofficial rules
  Fight — Each of those creatures deals damage equal to its power to the other.

• WWizards of the Coast2018-10-05
  Official Ruling
  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.
• WWizards of the Coast2018-10-05
  Official Ruling
  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.

Rulings via Scryfall