Resolute Watchdog — ruling 1

Resolute Watchdog can be the target of its own ability. The ability won’t resolve since it won’t have a legal target, and no creature will gain indestructible, but this does allow you to sacrifice Resolute Watchdog without another creature to target if you want to.

Resolute Watchdog : règles, fonctionnement et interactions (MTG)

Resolute Watchdog 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

Defender , Sacrifice this creature: Target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

How it works : Resolute Watchdog

Original English text — Wizards of the Coast / Scryfall

#1January 25, 2019· Wizards of the Coast
Resolute Watchdog can be the target of its own ability. The ability won’t resolve since it won’t have a legal target, and no creature will gain indestructible, but this does allow you to sacrifice Resolute Watchdog without another creature to target if you want to.
No other card is named in this ruling.