Giant Turtle — ruling 1

It only cares if it attacked on _your_ last turn, and not your opponent’s. This makes a difference if you take control of the Turtle during your opponent’s turn after it attacks. You can use it on your turn because it began your turn on the battlefield and because you did not attack with it last turn.

Giant Turtle : règles, fonctionnement et interactions (MTG)

Giant Turtle 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

This creature can't attack if it attacked during your last turn.

How it works : Giant Turtle

Original English text — Wizards of the Coast / Scryfall

#1October 4, 2004· Wizards of the Coast
It only cares if it attacked on _your_ last turn, and not your opponent’s. This makes a difference if you take control of the Turtle during your opponent’s turn after it attacks. You can use it on your turn because it began your turn on the battlefield and because you did not attack with it last turn.
No other card is named in this ruling.