Colossal Whale — ruling 1

If a creature token is exiled, it ceases to exist. It won't be returned to the battlefield.

Colossal Whale — ruling 2

Colossal Whale's triggered ability triggers and resolves during the declare attackers step, before blocking creatures are declared.

Colossal Whale — ruling 3

Auras attached to the exiled creature will be put into their owners' graveyards. Equipment attached to the exiled creature will become unattached and remain on the battlefield. Any counters on the exiled creature will cease to exist.

Colossal Whale — ruling 4

If Colossal Whale leaves the battlefield before its triggered ability resolves, the target creature won't be exiled.

Colossal Whale — ruling 5

In a multiplayer game, if Colossal Whale's owner leaves the game, the exiled card will return to the battlefield. Because the one-shot effect that returns the card isn't an ability that goes on the stack, it won't cease to exist along with the leaving player's spells and abilities on the stack.

Colossal Whale — ruling 6

The exiled card returns to the battlefield immediately after Colossal Whale leaves the battlefield. Nothing happens between the two events, including state-based actions. The two creatures aren't on the battlefield at the same time. For example, if the returning creature is a Clone, it can't enter the battlefield as a copy of Colossal Whale.

Colossal Whale — ruling 7

Colossal Whale's ability causes a zone change with a duration, a new style of ability that's somewhat reminiscent of older cards like Oblivion Ring. However, unlike Oblivion Ring, cards like Colossal Whale have a single ability that creates two one-shot effects: one that exiles the creature when the ability resolves, and another that returns the exiled card to the battlefield immediately after Colossal Whale leaves the battlefield.

Colossal Whale : règles, fonctionnement et interactions (MTG)

Colossal Whale 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

Islandwalk (This creature can't be blocked as long as defending player controls an Island.) Whenever this creature attacks, you may exile target creature defending player controls until this creature leaves the battlefield. (That creature returns under its owner's control.)

How it works : Colossal Whale

Original English text — Wizards of the Coast / Scryfall

#1July 1, 2013· Wizards of the Coast
If a creature token is exiled, it ceases to exist. It won't be returned to the battlefield.
No other card is named in this ruling.
#2July 1, 2013· Wizards of the Coast
Colossal Whale's triggered ability triggers and resolves during the declare attackers step, before blocking creatures are declared.
No other card is named in this ruling.
#3July 1, 2013· Wizards of the Coast
Auras attached to the exiled creature will be put into their owners' graveyards. Equipment attached to the exiled creature will become unattached and remain on the battlefield. Any counters on the exiled creature will cease to exist.
No other card is named in this ruling.
#4July 1, 2013· Wizards of the Coast
If Colossal Whale leaves the battlefield before its triggered ability resolves, the target creature won't be exiled.
No other card is named in this ruling.
#5July 1, 2013· Wizards of the Coast
In a multiplayer game, if Colossal Whale's owner leaves the game, the exiled card will return to the battlefield. Because the one-shot effect that returns the card isn't an ability that goes on the stack, it won't cease to exist along with the leaving player's spells and abilities on the stack.
No other card is named in this ruling.
#6July 1, 2013· Wizards of the Coast
The exiled card returns to the battlefield immediately after Colossal Whale leaves the battlefield. Nothing happens between the two events, including state-based actions. The two creatures aren't on the battlefield at the same time. For example, if the returning creature is a Clone, it can't enter the battlefield as a copy of Colossal Whale.
No other card is named in this ruling.
#7July 1, 2013· Wizards of the Coast
Colossal Whale's ability causes a zone change with a duration, a new style of ability that's somewhat reminiscent of older cards like Oblivion Ring. However, unlike Oblivion Ring, cards like Colossal Whale have a single ability that creates two one-shot effects: one that exiles the creature when the ability resolves, and another that returns the exiled card to the battlefield immediately after Colossal Whale leaves the battlefield.
No other card is named in this ruling.