{T}: Add {C}.
{2}, Exile a land card from your graveyard: Hostile Desert becomes a 3/4 Elemental creature until end of turn. It's still a land.
If Hostile Desert becomes a creature the same turn it enters the battlefield, you can’t attack with it or tap it for mana.
Desert is a land subtype with no special meaning. It doesn’t grant the land an intrinsic mana ability. Other cards may care about which lands are Deserts.