Chronomancer

Momentary Stasis. As an action, you can magically force a Large or smaller creature you can see within 60 feet of you to make a Constitution saving throw (DC: 15). Unless the saving throw is a success, the creature is encased in a field of magical energy until the end of your next turn or until the creature takes any damage. While encased in this way, the creature is incapacitated and has a speed of 0.

Spellcasting. The Chronomancer is a 4th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 15, +6 to hit with spell attacks). The Chronomancer has following Chronurgy spells prepared:
Cantrips (at will): Fire Bolt, Mind Sliver, Ray of Frost, Thunderclap
1st level (4 slots): Guiding Bolt, Longstrider, Mage Armor, Silvery Barbs
2nd level (3 slots): Chromatic Orb, Magic Missile
3rd level (2 slots): Counterspell, Haste, Slow

Fire Bolt. Ranged Weapon Attack: +6 to hit, range 120 ft., 1 target. Hit: 20 (2d10) fire damage.

Ray of Frost. Ranged Weapon Attack: +6 to hit, range 60 ft., 1 target. Hit: 16 (2d8) fire damage.

Chronal Shift. As a reaction, after you or a creature you can see within 30 ft. of you makes an attack roll, an ability check, or a saving throw, you can force the creature to reroll. You make this decision after you see whether the roll succeeds or fails. The target must use the result of the second roll.