Tidewalker

Creature - Elemental */*, 2U (3)
Tidewalker enters the battlefield with a time counter on it for each Island you control.

Vanishing (At the beginning of your upkeep, remove a time counter from this permanent. When the last is removed, sacrifice it.)

Tidewalker's power and toughness are each equal to the number of time counters on it.¹
Illus. Dave Kendall

Gatherer Card Rulings [Nov 2009]

• 2/1/2007: Unless something is boosting Tidewalker's toughness, when the last time counter is removed, it will be put into the graveyard as a state-based action for having 0 toughness before it can be sacrificed as the result of vanishing.
• 2/1/2007: If you don't control any Islands when Tidewalker enters the battlefield, its vanishing ability has no effect. (It enters the battlefield with no time counters on it, so neither of the vanishing triggers can trigger. See "Vanishing" in the General Notes section above.) On the other hand, it will be 0/0 and will be put into its owner's graveyard unless something is boosting its toughness.

Format Legality	Legal in Vintage, Legacy, Extended, MTGO Classic Banned in Standard
Printings (1/9)	Planar Chaos (Uncommon)