You create a magical tether of pulsing, golden force between two willing creatures you can see within range. The two creatures must be within 15 feet of each other. The tether remains as long as each tethered creature ends its turn within 15 feet of the other tethered creature. If a tethered creature ends its turn more than 15 feet away from its tethered partner, the spell ends. Though the tether appears as a thin line, its effect extends the full height of the tethered creatures and can affect prone or hovering creatures, provided the hovering creature hovers no higher than the tallest tethered creature. Any creature that touches the tether or ends its turn in a space the tether passes through must make a Strength saving throw. On a failure, a creature takes 3d6 force damage and is knocked prone. On a success, a creature takes half as much damage and isn't knocked prone. A creature that makes this saving throw, whether it succeeds or fails, can't be affected by the tether again until the start of your next turn.