Zeitgeist

The zeitgeist can take the Dash or Disengage action as a bonus action on each of its turns.

At the start of each of the zeitgeist’s turns, roll a die. On an even roll, its body stretches and speeds up as it takes on a darting form. On an odd roll, its body becomes more solid and slows down as it takes on a sluggish form. Its statistics are the same in each form, except as noted here.
* Darting Form. While in a Darting form, the zeitgeist’s Armor Class increases by 2, and its speed is 40 feet.
* Sluggish Form. While in a Sluggish form, the zeitgeist has resistance to bludgeoning, piercing, and slashing damage from nonmagical attacks, and its speed is 20 feet.

Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 6 (1d4 + 4) slashing damage plus 7 (2d6) force damage.

In its darting form, the zeitgeist makes three darting rend attacks. In its sluggish form, the zeitgeist makes two sluggish slam attacks.

Melee Weapon Attack: +6 to hit, reach 5 feet., one target. Hit: 12 (2d8 + 3) bludgeoning damage plus 7 (2d6) force damage. If the zeitgeist scores a critical hit, the target is also knocked prone.

The zeitgeist cries out, releasing some of its internal torment in a 30-foot cone. Each creature in that area must make a DC 15 Intelligence saving throw, taking 21 (6d6) psychic damage on a failed save, or half as much damage on a successful one.

When the zeitgeist takes damage or when it starts its turn afflicted with a condition, it can rewind time around it, preventing the damage or undoing the condition. It can use this reaction even while paralyzed or stunned.