Mindleecher — ruling 1

You may look at and play those cards even if Mindleecher leaves the battlefield. If another player gains control of Mindleecher, that player can’t look at or play the cards, and you still can.

Mindleecher — ruling 2

You can play lands this way only if you have remaining land plays available for the turn.

Mindleecher — ruling 3

You pay the costs for the exiled cards if you cast them. You may pay alternative costs such as mutate rather than a card’s mana cost.

Mindleecher — ruling 4

Mindleecher doesn’t change when you can cast the exiled cards. For example, if you exile a creature card without flash, you can cast it only during your main phase when the stack is empty.

Mindleecher — ruling 5

Casting the card causes it to leave exile. You can’t cast it multiple times.

Mindleecher — ruling 6

In a multiplayer game, if a player leaves the game, all cards that player owns leave as well. If you leave the game, any spells or permanents you control from Mindleecher are exiled, and any cards remaining in exile remain face down indefinitely. No player may look at them.

Mindleecher : règles, fonctionnement et interactions (MTG)

Mindleecher 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

Mutate (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.) Flying Whenever this creature mutates, exile the top card of each opponent's library face down. You may look at and play those cards for as long as they remain exiled.

How it works : Mindleecher

Original English text — Wizards of the Coast / Scryfall

#1April 17, 2020· Wizards of the Coast
You may look at and play those cards even if Mindleecher leaves the battlefield. If another player gains control of Mindleecher, that player can’t look at or play the cards, and you still can.
No other card is named in this ruling.
#2April 17, 2020· Wizards of the Coast
You can play lands this way only if you have remaining land plays available for the turn.
No other card is named in this ruling.
#3April 17, 2020· Wizards of the Coast
You pay the costs for the exiled cards if you cast them. You may pay alternative costs such as mutate rather than a card’s mana cost.
No other card is named in this ruling.
#4April 17, 2020· Wizards of the Coast
Mindleecher doesn’t change when you can cast the exiled cards. For example, if you exile a creature card without flash, you can cast it only during your main phase when the stack is empty.
No other card is named in this ruling.
#5April 17, 2020· Wizards of the Coast
Casting the card causes it to leave exile. You can’t cast it multiple times.
No other card is named in this ruling.
#6April 17, 2020· Wizards of the Coast
In a multiplayer game, if a player leaves the game, all cards that player owns leave as well. If you leave the game, any spells or permanents you control from Mindleecher are exiled, and any cards remaining in exile remain face down indefinitely. No player may look at them.
No other card is named in this ruling.