Leeches

A hungry leech is a determined predator that slithers underneath loose clothing in search of bare flesh. Characters wading through murky waters or trudging through damp earth may spot an approaching leech with a successful DC 15 Wisdom (Perception) check or if they have passive Wisdom (Perception) of 15 or more. If the check succeeds, the character can squash the leech or collect it for another purpose.

An undetected leech latches onto the creature and searches for an opening to grant it access to the target’s exposed skin. When it reaches its destination, it begins feeding. Leech bites do not evoke immediate pain, so there is a good chance that the leech’s dining goes unnoticed. Still, a successful DC 10 Constitution saving throw alerts the character to the animal’s uninvited presence. A character aware of the chewing sensation instantly knows where the discomfort is coming from on his body. If he can see the attachment site, he can kill or remove the leech. A creature that fails the preceding Constitution save remains unaware of the leech’s presence unless he surreptitiously finds it during a visual inspection of his skin.

The threat from leeches is the anticoagulant they secrete when feeding.

Improperly detaching a leech can result in profuse bleeding. The best method for removing a leech can be determined by a character with a successful DC 10 Intelligence check. The removal of the leech can be accomplished with a successful DC 10 Wisdom (Medicine) check. Failure to properly remove the leech results in the host taking 1 necrotic damage per round for 1d4 rounds.