Leviathan of Species XR217

Defender, Trample
Sacrifice a Land: Each other player sacrifices a
Land. Until the end of the turn it loses Defender,
use this as a sorcery and only once a turn.
Delve (Each card you exile from your graveyard
while casting this spell pays for {1}.)
Slivers you control get Delve and the Leviathan
type
Nobody realized magnitude of the covered oceans'
life. Or that while unmapped, cavernous tunnels
might surface the anywhere.