Oko, the Trickster — ruling 1

If Oko becomes a creature the same turn he enters the battlefield, you can't attack with him or use any of his {T} abilities (if he gains any).

Oko, the Trickster — ruling 2

While Oko is a creature, he isn't a planeswalker. Damage dealt to him won't cause him to lose loyalty.

Oko, the Trickster — ruling 3

If the target creature is an illegal target by the time Oko's second ability tries to resolve, the ability won't resolve. Damage that would be dealt to Oko won't be prevented.

Oko, the Trickster — ruling 4

Oko copies the printed values of the target creature. It won't copy counters on that creature or effects that have changed its power, toughness, types, color, or so on. Notably, it won't copy effects that made the target creature become a creature if it isn't normally a creature.

Oko, the Trickster — ruling 5

If the target creature is copying something else, then Oko becomes a copy of whatever that creature copied.

Oko, the Trickster — ruling 6

Oko's last ability affects only creatures you control at the time it resolves. Creatures you begin to control later in the turn won't be 10/10.

Oko, the Trickster — ruling 7

Any effects that modify a creature's power and/or toughness without setting them to a specific number or value will apply after its base power and toughness are set, regardless of the order in which those effects were created. The same is true of counters that modify its power and toughness.

Oko, the Trickster : règles, fonctionnement et interactions (MTG)

Oko, the Trickster 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

+1: Put two +1/+1 counters on up to one target creature you control. 0: Until end of turn, Oko becomes a copy of target creature you control. Prevent all damage that would be dealt to him this turn. −7: Until end of turn, each creature you control has base power and toughness 10/10 and gains trample.

Complete guide

Oko, the Trickster is a versatile planeswalker that excels at buffing your board and blending into the battlefield. By transforming into other creatures and shielding himself from damage, he offers a unique blend of offensive pressure and survivability.

Copying and Protection

Oko's second ability allows him to become a copy of a creature you control until end of turn. While he is a creature, he ceases to be a planeswalker, meaning he cannot lose loyalty from damage. As an added benefit, this ability prevents all damage that would be dealt to him for the rest of the turn, making him an incredibly safe attacker or blocker.

Resolution and Interaction

When Oko copies a creature, he uses the 'printed values' of that card. He does not copy any counters, temporary buffs, or continuous effects currently affecting that creature. If you target a creature that is already a copy, Oko will become a copy of whatever that creature is currently mimicking. Note that if Oko enters the battlefield and immediately becomes a creature, he is still subject to 'summoning sickness' and cannot attack unless he has haste.

Common Mistakes

A frequent error is assuming Oko's ultimate ability (+7) affects creatures that enter the battlefield later in the turn; it only applies to creatures you control at the moment the ability resolves. Additionally, remember that while Oko is a creature, he cannot use other loyalty abilities since you can only activate one loyalty ability of a permanent per turn during your main phase.

Strategic Timing

Use the +1 ability early to build a board presence and increase Oko's loyalty. Once you have a high-impact creature, use the 0 ability to double your threats while keeping Oko safe from combat damage. Save the -7 ultimate for a finishing blow, as 10/10 creatures with trample are often impossible to block effectively.

Interaction examples

Securing the Finish

Oko's Hospitality

If you have Oko, the Trickster on the battlefield and cast Oko's Hospitality, your creatures' base power and toughness become 3/3. If you then resolve Oko's -7 ability, their base power and toughness will become 10/10 instead. Because both effects set 'base' values, the most recent effect (the -7 ability) takes precedence.

Spirit Mimicry

Ugin, the Ineffable

If Ugin, the Ineffable uses his +1 to create a 2/2 Spirit token, you can use Oko's 0 ability to become a copy of that Spirit. Oko will be a 2/2 Spirit creature until end of turn and will not be a planeswalker during this time. Any damage dealt to Oko-Spirit will be prevented, and he will not lose loyalty counters if he takes damage in combat.

Guide written with AI from the official text and rulings. Official English text prevails.

How it works : Oko, the Trickster

Original English text — Wizards of the Coast / Scryfall

#1October 4, 2019· Wizards of the Coast
If Oko becomes a creature the same turn he enters the battlefield, you can't attack with him or use any of his abilities (if he gains any).
No other card is named in this ruling.
#2October 4, 2019· Wizards of the Coast
While Oko is a creature, he isn't a planeswalker. Damage dealt to him won't cause him to lose loyalty.
No other card is named in this ruling.
#3October 4, 2019· Wizards of the Coast
If the target creature is an illegal target by the time Oko's second ability tries to resolve, the ability won't resolve. Damage that would be dealt to Oko won't be prevented.
No other card is named in this ruling.
#4October 4, 2019· Wizards of the Coast
Oko copies the printed values of the target creature. It won't copy counters on that creature or effects that have changed its power, toughness, types, color, or so on. Notably, it won't copy effects that made the target creature become a creature if it isn't normally a creature.
No other card is named in this ruling.
#5October 4, 2019· Wizards of the Coast
If the target creature is copying something else, then Oko becomes a copy of whatever that creature copied.
No other card is named in this ruling.
#6October 4, 2019· Wizards of the Coast
Oko's last ability affects only creatures you control at the time it resolves. Creatures you begin to control later in the turn won't be 10/10.
No other card is named in this ruling.
#7October 4, 2019· Wizards of the Coast
Any effects that modify a creature's power and/or toughness without setting them to a specific number or value will apply after its base power and toughness are set, regardless of the order in which those effects were created. The same is true of counters that modify its power and toughness.
No other card is named in this ruling.

Interactions with other cards

These cards' text mentions Oko, the Trickster.

Oko's Hospitality

Creatures you control have base power and toughness 3/3 until end of turn. You may search your library and/or graveyard for a card named Oko, the Trickster, reveal it, and put it into your hand. If you search your library this way, shuffle.