Tidewalker

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 creature. When the last is removed, sacrifice it.)
Tidewalker’s power and toughness are each equal to the number of time counters on it.

Calciderm

Shroud (This creature can’t be the target of spells or abilities.)
Vanishing 4 (This creature enters the battlefield with four time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)