Mite

While within 30 feet of a mite that can see it, a non-fey creature has disadvantage on Dexterity checks and Dexterity saving throws.

Melee or Ranged Weapon Attack: +4 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 4 (1d4 + 2) piercing damage.

The mite places a hex on a creature it can see within 60 feet of it for 1 minute. If the mite is hidden, using this ability does not reveal its location. While the creature is affected by this hex, whenever it makes an attack roll, an ability check, or a saving throw, it must roll a d6 and subtract the number rolled from the d20 roll. On any turn in which it suffers the effect of the hex, the target can attack an ally as a reaction, ignoring the effect of the hex when it does so. It can then ignore the effect of the hex until the end of its turn.