Mariner's Curse

What if this is animated by an Enchantress?

If an animated Mariner's Curse moves and enters a water site, it will submerge itself (if possible) and die (assuming it doesn't have Submerge). If it hasn't died, it will then return itself to its owner's hand. It will not have a chance to attack before its effect resolves, because the move happens before the attack.

If I Grapple Shot a minion with Submerge through an area affected by Mariner's Curse, what happens?

When the Grapple Shot projectile hits the unit, the game adds specific movement steps for the ally to the Storyline: Move A () -> B (), B () -> C (). Then, we start resolving those steps. If is on B, once the being dragged reaches B, it will be submerged, and live. Then the game tries to resolve B () -> C (), which fails, since the isn't on the of B anymore. Thus, 's no from since it didn't reach the hit 's .