Incorporeal Movement. The specter can move through other creatures and objects as if they were Difficult
Terrain. It takes 5 (1d10) Force damage if it ends its turn inside an object.
Sunlight Sensitivity. While in sunlight, the specter has Disadvantage on ability checks and attack rolls.
Actions
Life Drain. Melee Attack Roll: +4, reach 5 ft. Hit: 7 (2d6) Necrotic damage. If the target is a creature, its Hit Point maximum decreases by an amount equal to the damage taken. 327 Sphinxes
Condition immunities: charmed, exhaustion, grappled, paralyzed, petrified, poisoned, prone, restrained, unconscious. Senses: Darkvision 60 ft.; Passive Perception 10. Languages: Understands Common plus one other language but can't speak. Speed: 30 ft., Fly 50 ft. (hover).
RollQuest ships the D&D 2024 SRD as a content pack, on a 5e character sheet that does the maths - roll from the sheet and let the numbers work themselves out. Free to start.