Restless Reef
Land
This land enters tapped.
: Add 
or 
.
: Until end of turn, this land becomes a 4/4 blue and black Shark creature with deathtouch. It's still a land.
Whenever this land attacks, target player mills four cards.
Illustrated by
The Lost Caverns of Ixalan#282RareEnglishLegality
Rulings
Nov 10, 2023
If this becomes a creature but you haven't controlled it continuously since your most recent turn began, you won't be able to activate its mana ability or attack with it that turn.
Nov 10, 2023
If this becomes a creature because of an effect other than its own ability, its last ability will still trigger whenever it attacks.