火星の水ゾンビ

島渡り
最後は水が勝つ — 火星の水ゾンビが攻撃するたび、クリーチャーや土地のうちこれでない１つを対象とする。それの上に洪水カウンター１個を置く。それがクリーチャーであるなら、それは火星の水ゾンビのコピーになる。それが土地であるなら、それは他のタイプに加えて島になる。

The Flood of Mars

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Water Always Wins — Whenever The Flood of Mars attacks, put a flood counter on another target creature or land. If it's a creature, it becomes a copy of The Flood of Mars. If it's a land, it becomes an Island in addition to its other types.

Doctor Who

If the target is both a creature and a land as the triggered ability resolves, it will become a copy of The Flood of Mars. Excepting some very unusual cases, that copy won't be a land, so it won't also become an Island.