Jaddi Lifestrider — ruling 1

You don’t choose which creatures to tap until the ability resolves. You may tap Jaddi Lifestrider itself this way, assuming it’s still on the battlefield untapped by this time.

Jaddi Lifestrider : règles, fonctionnement et interactions (MTG)

Jaddi Lifestrider 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 tap any number of untapped creatures you control. You gain 2 life for each creature tapped this way.

How it works : Jaddi Lifestrider

Original English text — Wizards of the Coast / Scryfall

#1June 15, 2010· Wizards of the Coast
You don’t choose which creatures to tap until the ability resolves. You may tap Jaddi Lifestrider itself this way, assuming it’s still on the battlefield untapped by this time.
No other card is named in this ruling.