You create a magical zone that incites magical fatigue in a 10-foot-radius sphere centered on a point of your choice within range. Until the spell ends, a creature that enters the spell's area for the first time on a turn or starts its turn there can only use up to half of its remaining movement rounded down. The creature can use the dash action in order to gain back its full walking speed. If the creature is under the effects of the haste spell, the spell instantly ends when they enter or start their turn in the zone and they cannot move or take actions until the start of their next turn. Additionally, any creature that ends their turn in the zone must make a Constitution saving throw. On a failed save, the creature instantly gains one level of exhaustion. The creature repeats this saving throw every time it ends its turn in the zone, gaining an additional level of exhaustion when it fails. When the spell ends, any levels of exhaustion gained from this spell are removed.