Stirge

[ Strige ]
Tiny beast, unaligned
Armor Class 14 (natural armor)
Hit Points 2 (1d4)
Speed 10 ft., fly 40 ft.
STR
4 (-3)
DEX
16 (+3)
CON
11 (+0)
INT
2 (-4)
WIS
8 (-1)
CHA
6 (-2)
Senses darkvision 60 ft., passive Perception 9
Languages
Challenge 1/8 (25 XP)
Actions

Blood Drain. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 5 (1d4 + 3) piercing damage, and the stirge attaches to the target. While attached, the stirge doesn't attack. Instead, at the start of each of the stirge's turns, the target loses 5 (1d4 + 3) hit points due to blood loss. The stirge can detach itself by spending 5 feet of its movement. It does so after it drains 10 hit points of blood from the target or the target dies. A creature, including the target, can use its action to detach the stirge.

This horrid monster looks like a cross between a large bat and an oversized mosquito. Its legs end in sharp pincers, and its long, needle-like proboscis slashes the air as it seeks to feed on the blood of living creatures.
Monster Manual (SRD)
  1. DnD 5e Monsters › Stirge
Stirge