Kurbis, Harvest Celebrant — ruling 1

Kurbis enters with a number of +1/+1 counters on it equal to the total mana spent to cast it, and that number usually won't be the same as X. If you cast Kurbis for {G}{G}, it will enter the battlefield with two +1/+1 counters on it.

Kurbis, Harvest Celebrant — ruling 2

If you copy Kurbis while it is on the stack (perhaps using an effect like that of Double Major), the copy wasn't cast, so no mana was spent to cast it. That Kurbis will enter with zero +1/+1 counters on it.

Kurbis, Harvest Celebrant — ruling 3

Similarly, if you create a token that's a copy of Kurbis, or if a card enters the battlefield as a copy of Kurbis without being cast, it enters with zero +1/+1 counters on it.

Kurbis, Harvest Celebrant — ruling 4

If a resolving spell enters the battlefield as a copy of Kurbis, it will enter the battlefield with a number of +1/+1 counters equal to the mana spent to cast the spell. For example, if you spend {3}{U} to cast Clone and choose to have it copy Kurbis as it enters the battlefield, it will enter with four +1/+1 counters on it because four mana was spent to cast Clone.

Kurbis, Harvest Celebrant — ruling 5

Once the activated ability resolves, damage will be prevented even if the creature later loses all of its +1/+1 counters.

Kurbis, Harvest Celebrant : règles, fonctionnement et interactions (MTG)

Kurbis, Harvest Celebrant 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

Kurbis enters with a number of +1/+1 counters on it equal to the amount of mana spent to cast it. Remove a +1/+1 counter from Kurbis: Prevent all damage that would be dealt this turn to another target creature with a +1/+1 counter on it.

How it works : Kurbis, Harvest Celebrant

Original English text — Wizards of the Coast / Scryfall

#1September 24, 2021· Wizards of the Coast
Kurbis enters with a number of +1/+1 counters on it equal to the total mana spent to cast it, and that number usually won't be the same as X. If you cast Kurbis for , it will enter the battlefield with two +1/+1 counters on it.
No other card is named in this ruling.
#2September 24, 2021· Wizards of the Coast
If you copy Kurbis while it is on the stack (perhaps using an effect like that of Double Major), the copy wasn't cast, so no mana was spent to cast it. That Kurbis will enter with zero +1/+1 counters on it.
No other card is named in this ruling.
#3September 24, 2021· Wizards of the Coast
Similarly, if you create a token that's a copy of Kurbis, or if a card enters the battlefield as a copy of Kurbis without being cast, it enters with zero +1/+1 counters on it.
No other card is named in this ruling.
#4September 24, 2021· Wizards of the Coast
If a resolving spell enters the battlefield as a copy of Kurbis, it will enter the battlefield with a number of +1/+1 counters equal to the mana spent to cast the spell. For example, if you spend to cast Clone and choose to have it copy Kurbis as it enters the battlefield, it will enter with four +1/+1 counters on it because four mana was spent to cast Clone.
No other card is named in this ruling.
#5September 24, 2021· Wizards of the Coast
Once the activated ability resolves, damage will be prevented even if the creature later loses all of its +1/+1 counters.
No other card is named in this ruling.