Final-Word Phantom

The 1/4 flying body is the tell: this is a wall built to survive the turns it takes for its real job to matter, and that job is a permission-shaped one. Flash already lets you hold up mana and hit your window at instant speed, but the static ability extends that permission to your entire hand, and only during each opponent's end step. The design is doing something quietly precise with the turn structure: it opens a recurring flash window on the last passable point of every opponent's turn, the moment when their untapped mana is least useful to them and information is most complete. You get to resolve sorceries, cast the expensive sorcery-speed spell you would normally telegraph a turn early, and do it with the full board state of their turn already on the table. It converts your whole deck into a reactive one without asking you to build a reactive deck. The Spirit Detective typing and the flavor of the vigilant watcher waiting for the perfect moment map neatly onto the mechanic: nothing acts until the end of the case, then everything can. What limits it is ownership of the window: the effect belongs to opponents' end steps, so it is inert on your own turn and does nothing to accelerate your development. It rewards patience and a hand of high-impact cards over a curve of cheap ones, a genuinely different way to sequence a game than most blue permanents ask for.