Waves of Aggression — ruling 1

Casting a card by using its retrace ability works just like casting any other spell, with two exceptions: You're casting it from your graveyard rather than your hand, and you must discard a land card in addition to any other costs.

Waves of Aggression — ruling 2

If it's somehow not a main phase when Waves of Aggression resolves, all it does is untap all creatures that attacked that turn. No new phases are created.

Waves of Aggression — ruling 3

A retrace card cast from your graveyard follows the normal timing rules for its card type.

Waves of Aggression — ruling 4

If the active player casts a spell that has retrace, that player may cast that card again after it resolves, before another player can remove the card from the graveyard. The active player has priority after the spell resolves, so they can immediately cast a new spell. Since casting a card with retrace from the graveyard moves that card onto the stack, no one else would have the chance to affect it while it's still in the graveyard.

Waves of Aggression — ruling 5

When a retrace card you cast from your graveyard resolves, fails to resolve, or is countered, it's put back into your graveyard. You may use the retrace ability to cast it again.

Waves of Aggression — ruling 6

Waves of Aggression untaps all creatures that attacked this turn, not just those that attacked during the most recent combat phase.

Waves of Aggression : règles, fonctionnement et interactions (MTG)

Waves of Aggression 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

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase. Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

How it works : Waves of Aggression

Original English text — Wizards of the Coast / Scryfall

#1August 1, 2008· Wizards of the Coast
Casting a card by using its retrace ability works just like casting any other spell, with two exceptions: You're casting it from your graveyard rather than your hand, and you must discard a land card in addition to any other costs.
No other card is named in this ruling.
#2August 1, 2008· Wizards of the Coast
If it's somehow not a main phase when Waves of Aggression resolves, all it does is untap all creatures that attacked that turn. No new phases are created.
No other card is named in this ruling.
#3August 1, 2008· Wizards of the Coast
A retrace card cast from your graveyard follows the normal timing rules for its card type.
No other card is named in this ruling.
#4August 1, 2008· Wizards of the Coast
If the active player casts a spell that has retrace, that player may cast that card again after it resolves, before another player can remove the card from the graveyard. The active player has priority after the spell resolves, so they can immediately cast a new spell. Since casting a card with retrace from the graveyard moves that card onto the stack, no one else would have the chance to affect it while it's still in the graveyard.
No other card is named in this ruling.
#5August 1, 2008· Wizards of the Coast
When a retrace card you cast from your graveyard resolves, fails to resolve, or is countered, it's put back into your graveyard. You may use the retrace ability to cast it again.
No other card is named in this ruling.
#6August 1, 2008· Wizards of the Coast
Waves of Aggression untaps all creatures that attacked this turn, not just those that attacked during the most recent combat phase.
No other card is named in this ruling.