Legend has it that Serpents used to be bigger, but how could that be?

30th Anniversary Edition

Sea Serpent

Sea Serpent can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Sea Serpent.

Legend has it that serpents used to be bigger, but how could that be?

Islandhome (If defending player controls no islands, this creature cannot attack. If you control no islands, bury this creature.)

Cannot attack if defending player controls no islands. If at any time you control no islands, bury Sea Serpent.

Serpent cannot attack unless opponent has islands in play. Serpent is buried immediately if at any time controller has no islands in play.

Serpent cannot attack unless opponent has islands in play. Serpent is destroyed immediately if at any time controller has no islands in play.

Serpent cannot attack unless opponent has islands in play.
Serpent is destroyed immediately if at any time controller has no islands in play.