Leviathan, God of the Deep

Islandwalk, Haste
Flood {x} number of opponents basic lands.
(That land is an Island in addition to its other types
for as long as it has a flood counter on it.)
Whenever Leviathan, God of the Deep attacks
place a flood counter on a basic land.
If you control twenty basic lands give Leviathan,
God of the Deep indestructible.