Giant Leech (5e Creature)
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Medium beast, unaligned
Amphibious. The leech can breathe air and water.
Salt Susceptibility. For every handful of salt thrown on the leech, it takes 3 (1d6) acid damage.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 5 (1d6 + 2) piercing damage, and the leech attaches to the target. While attached, the leech doesn't attack. Instead, at the start of each of the leech's turns, the target loses 5 (1d6 + 2) hit points due to blood loss.
Stories are told of leeches the size of men that wander primeval swamps, stealthily moving among detritus and decomposing leaves to strike at unwary travellers. These giant leeches occasionally hunt alongside other creatures that drink blood, like stirges, though some vampires keep these oversized leeches as pets and companions, treating them almost like bloodthirsty dogs.