Leech infested waters are any pool of slow moving or stagnant water where hordes of blood-sucking leeches thrive. Fictional leech infested waters are often found in mirky swamps or uncharted rivers where these leeches quickly latch onto and drink the blood of any unfortunate adventurer that enters their depths. In game worlds they may act as a terrain hazard or location where leeches can be found as enemies, whereas in narratives the sudden realization that a body of water contains leeches is a common story element. Leeches may be an opportunity to insert a fictional disease.