Undead Fortitude. If damage reduces the zombie to 0 hit points, it must make a Constitution saving throw with a DC of 5 + 1 for each time the zombie uses this trait, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hit point and is knocked prone. On a failed save the zombie dies

Necrotic Rejuvenation. When the zombie is hit with necrotic damage, it takes no damage and instead is healed for half the damage taken.

Fey ancestry.  The drow has advantage on saving throws against being charmed, and magic can’t put the drow to sleep.

Innate spellcasting. The drow’s spellcasting ability is Charisma (spell save DC 6). It can innately cast the following spells, requiring no material components:

At will: dancing lights

1/day each: darkness faerie fire

Sunlight sensitivity.  While in sunlight, the drow has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight 

Slam. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage.