Multiattack. The specter makes two scythe attacks.
Scythe. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 4) piercing damage, or 14 (2d6 + 7) slashing damage if raging plus 13 (3d8) cold damage.
North Wind (Recharge 5–6). The specter magically emits psychic energy in a 60-foot cone. Each creature in that area must succeed on a DC 15 Wisdom saving throw or take 22 (5d8) cold damage and be stunned for 1 minute. The stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Reap Memory (3/Day). The specter touches one incapacitated creature and chooses 1 hour from among the past 24. Unless the creature succeeds on a DC 15 Intelligence saving throw, the creature loses all memory of that hour. The creature regains the memory only if the specter dies within the next 24 hours.
Mindless Rage (2/Short Rest). While raging, you have resistance to all damage except psychic damage. You have an advantage on Strength checks and Strength saving throws and when you make a melee weapon attack using Strength, you gain a +3 bonus to the damage roll.