Intellect Devourer — ruling 1

You must still follow all normal timing rules for cards played this way. For example, you may play a land exiled this way only during your main phase and only if you haven't played a land yet this turn.

Intellect Devourer — ruling 2

If Intellect Devourer leaves the battlefield before the Devour Intellect ability resolves, opponents won't exile any cards from their hands.

Intellect Devourer — ruling 3

If a card exiled with the Devour Intellect leaves exile for any reason (most likely because it was played using the Body Thief ability), it won't be returned to the opponent's hand if Intellect Devourer leaves the battlefield.

Intellect Devourer : règles, fonctionnement et interactions (MTG)

Intellect Devourer 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

Devour Intellect — When this creature enters, each opponent exiles a card from their hand until this creature leaves the battlefield. Body Thief — You may play lands and cast spells from among cards exiled with this creature. If you cast a spell this way, you may spend mana as though it were mana of any color to cast it.

How it works : Intellect Devourer

Original English text — Wizards of the Coast / Scryfall

#1June 10, 2022· Wizards of the Coast
You must still follow all normal timing rules for cards played this way. For example, you may play a land exiled this way only during your main phase and only if you haven't played a land yet this turn.
No other card is named in this ruling.
#2June 10, 2022· Wizards of the Coast
If Intellect Devourer leaves the battlefield before the Devour Intellect ability resolves, opponents won't exile any cards from their hands.
No other card is named in this ruling.
#3June 10, 2022· Wizards of the Coast
If a card exiled with the Devour Intellect leaves exile for any reason (most likely because it was played using the Body Thief ability), it won't be returned to the opponent's hand if Intellect Devourer leaves the battlefield.
No other card is named in this ruling.