Flying Sword

Small construct, unaligned
Armor Class 17 (natural armor)
Hit Points 17 (5d6)
Speed 0 ft., fly 50 ft. (hover)
STR
12 (+1)
DEX
15 (+2)
CON
11 (+0)
INT
1 (-5)
WIS
5 (-3)
CHA
1 (-5)
Saving Throws Dex +4
Damage Immunities poison, psychic
Condition Immunities blinded, charmed, deafened, frightened, paralyzed, petrified, poisoned
Senses blindsight 60 ft. (blind beyond this radius), passive Perception 7
Languages
Challenge 1/4 (50 XP)

Antimagic Susceptibility. The sword is incapacitated while in the area of an antimagic field. If targeted by dispel magic, the sword must succeed on a Constitution saving throw against the caster's spell save DC or fall unconscious for 1 minute.

False Appearance. While the sword remains motionless and isn't flying, it is indistinguishable from a normal sword.

Actions

Longsword. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 5 (1d8 + 1) slashing damage.

A magically animated flying sword dances through the air, fighting like a warrior that can't be injured.
Monster Manual (SRD)
Flying Sword