Littjara Mirrorlake — ruling 1

The token copies exactly what is printed on the creature and nothing else (unless that creature is a token or is copying something else; see below). The token doesn't copy whether that creature is tapped or untapped, whether it has any counters on it, whether it has any Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on.

Littjara Mirrorlake — ruling 2

If the target creature is itself a token, the token created by Littjara Mirrorlake's ability copies the original characteristics of that token as stated by the effect that created it.

Littjara Mirrorlake — ruling 3

If the target creature is copying something else, the token you create will use the copiable values of the target creature. In most cases, it will be a copy of whatever the target creature is copying. If it's copying a permanent or card with {X} in its mana cost, X is 0.

Littjara Mirrorlake — ruling 4

If the copied creature has {X} in its mana cost, X is 0.

Littjara Mirrorlake — ruling 5

Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any “As [this creature] enters the battlefield” or “[This creature] enters the battlefield with” abilities of the copied creature will also work.

Littjara Mirrorlake : règles, fonctionnement et interactions (MTG)

Littjara Mirrorlake 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 land enters tapped. : Add . , , Sacrifice this land: Create a token that's a copy of target creature you control, except it enters with an additional +1/+1 counter on it. Activate only as a sorcery.

How it works : Littjara Mirrorlake

Original English text — Wizards of the Coast / Scryfall

#1February 5, 2021· Wizards of the Coast
The token copies exactly what is printed on the creature and nothing else (unless that creature is a token or is copying something else; see below). The token doesn't copy whether that creature is tapped or untapped, whether it has any counters on it, whether it has any Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on.
Card named in this ruling
Copy
#2February 5, 2021· Wizards of the Coast
If the target creature is itself a token, the token created by Littjara Mirrorlake's ability copies the original characteristics of that token as stated by the effect that created it.
No other card is named in this ruling.
#3February 5, 2021· Wizards of the Coast
If the target creature is copying something else, the token you create will use the copiable values of the target creature. In most cases, it will be a copy of whatever the target creature is copying. If it's copying a permanent or card with in its mana cost, X is 0.
Card named in this ruling
Copy
#4February 5, 2021· Wizards of the Coast
If the copied creature has in its mana cost, X is 0.
No other card is named in this ruling.
#5February 5, 2021· Wizards of the Coast
Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any “As [this creature] enters the battlefield” or “[This creature] enters the battlefield with” abilities of the copied creature will also work.
No other card is named in this ruling.