Soulsworn Spirit

Detain is a tempo mechanic dressed up as removal, and this is the version that points the effect at both ends of the combat math. The body cannot be blocked, so the two damage is guaranteed regardless of what the opponent fields; the enters trigger then turns off whichever creature would otherwise have mattered on the swing back. The detained creature does not die, but for a full turn cycle it cannot attack, cannot block, and cannot crack its own activated abilities, which is the part that earns the card its keep against a mana dork, a planeswalker-protecting wall, or a creature whose value lives in a tap ability. So the detain is not clearing the path for the attack: the unblockable clause already does that. It is buying a defensive turn, freezing the opponent's best attacker or blocker while you connect for free. The trade is that the lock is temporary and the trigger fires once on entry, so this is a beater that opens a single window rather than a permanent answer; it gets its damage in and stunts one threat for a turn, then hands the board back intact. The fragile toughness keeps the rate from running away. As a demonstration of why this kind of soft interaction landed in blue and white, it is unusually clean: it resets instead of destroys, respects the opponent's permanents, and measures its tempo swing in turns rather than cards.