Rune of the Surging Gloomtide

Once per battle, at the end of your movement phase, you can say that the bearer will summon a Gloomtide Shipwreck from the ethersea. If you do so, you can set up 1 Gloomtide Shipwreck wholly within 12" of the bearer and more than 3" from all models, objectives, other terrain features, endless spells, and invocations, and add it to your army.