Syocrax' Bodkin

You put a nail in the footprint left by a creature. The target makes a saving throw on Intelligence. On a failed save, the speed of the target is reduced to 0 for the duration. On a successful save, the target is immune to the spell for 24h. When the target takes damage it can spend his reaction to remake the saving throw. The spell ends earlier if the nail is removed, if the target is moved or knocked prone by an external agent or if the target or the nail are subject ot a remove curse or similar spells. The nail and the target must be in the same plane, if not the spell is wasted. When the spell ends the nail falls.

(If the nail is taken from a coffin the saving throw is made with disadvantage)