X Marks the Spot

You mark a creature or object's current location, causing an illusory X to appear beneath it. For the next minute, all movement that the object makes is tracked, illustrated further as a dotted line coming from the X, akin to a treasure map. At any point during this time, you can use a bonus action to cause the target to instantly return to the location of the X, although it retains its current orientation etc. If the area immediately surrounding the X has become impassable (e.g. if a large rock has been placed over it), the target is returned to the nearest occupiable space to the X. When the target is returned, the illusory X and path dissipate

If your concentration on this spell breaks, the X and path are destroyed but the target does not return. If your concentration is successful for the spell's whole duration, the target is returned to the X.