Liver Leech (5e Creature)
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Tiny undead, lawful evil
Death Wail. When a liver leech dies it sends out a telepathic message to it's creator, which extends for up to 3 miles in all directions. If it's creator is within range, it knows exactly where the liver leech was when it died.
Easy to Conjure. Because the magic that creates this undead is so weak, a necromantic entity may have 5 liver leeches for every 5 Hit Dice it possesses.
Spider Climb. The liver leech can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Spy Adaptation. Whenever a liver leech has spent 4 hours in a terrain it gains a natural covering similar to its environment such as sprouting grass or moss in the forest. While it remains in an environment which it has adapted to, it has advantage on Dexterity (Stealth) checks made to hide.
Telepathic Bond. Although the liver leech cannot speak a language it can create telepathic utterances that can be heard and understood by its creator as long as they are no more than 120 feet from each other.
Bite. Melee Weapon Attack: +0 to hit, reach 5 ft., one target. Hit: 1 piercing damage.
Liver leeches are raised from freshly deceased bodies. They are small, silent, and easily hidden so that they work well as early alarm systems or spies. While they are called liver leeches, this is somewhat of a misnomer. Once the ritual is done the host's liver, stomach, lungs, and heart all become separate liver leeches, looking just like their respective organ but gaining large black bug-like eyes and many small suction cup-like feet. They also gain a small sharp mouth to defend themselves. The stats of a liver leech do not change regardless of what organ it is spawned from.