Tiny Monstrosity, Unaligned
Actions
Proboscis. Melee Attack Roll: +5, reach 5 ft. Hit: 6 (1d6 + 3) Piercing damage, and the stirge attaches to the target. While attached, the stirge can't make Proboscis attacks, and the target takes 5 (2d4) Necrotic damage at the start of each of the stirge's turns. The stirge can detach itself by spending 5 feet of its movement. The target or a creature within 5 feet of it can detach the stirge as an action.
Found on p.299 of MM2025 (Free Rules)