Advanced Tactics (RR04g) [Unknown Event]

When this enchantment enters, create a 5x5 grid for as long as it remains on the battlefield. Starting with the top left space and skipping every other space, choose a random creature and put it in the grid. As a creature enters, its controller puts it in an empty space. Creatures can't block creatures they aren't orthogonally adjacent to. {1}: Move target creature you control one space left, right, up, or down. Any player may activate this ability.