Vanish into Memory — ruling 1

Vanish into Memory cares about the creature's power just before it left the battlefield and its toughness just after it returns to the battlefield. For example, if you target a 2/2 creature with two +1/+1 counters on it, you'll draw four cards, then when it returns to the battlefield without any counters on it, you'll discard two cards.

Vanish into Memory — ruling 2

If the creature exiled with Vanish into Memory never returns to the battlefield (because it was a token creature, for example), you don't discard any cards.

Vanish into Memory — ruling 3

If the creature exiled with Vanish into Memory isn't a creature card (for example, a crewed Vehicle), that card will still be returned to the battlefield, but not as a creature. Since the card returned to the battlefield has no toughness, you discard no cards.

Vanish into Memory : règles, fonctionnement et interactions (MTG)

Vanish into Memory 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

Exile target creature. You draw cards equal to that creature's power. At the beginning of your next upkeep, return that card to the battlefield under its owner's control. If you do, discard cards equal to that creature's toughness.

How it works : Vanish into Memory

Original English text — Wizards of the Coast / Scryfall

#1March 14, 2017· Wizards of the Coast
Vanish into Memory cares about the creature's power just before it left the battlefield and its toughness just after it returns to the battlefield. For example, if you target a 2/2 creature with two +1/+1 counters on it, you'll draw four cards, then when it returns to the battlefield without any counters on it, you'll discard two cards.
No other card is named in this ruling.
#2March 14, 2017· Wizards of the Coast
If the creature exiled with Vanish into Memory never returns to the battlefield (because it was a token creature, for example), you don't discard any cards.
No other card is named in this ruling.
#3March 14, 2017· Wizards of the Coast
If the creature exiled with Vanish into Memory isn't a creature card (for example, a crewed Vehicle), that card will still be returned to the battlefield, but not as a creature. Since the card returned to the battlefield has no toughness, you discard no cards.
No other card is named in this ruling.