Oyster Clampers at rest
Oyster Clampers are Diminutive, carnivorous oysters that inhabit Cay Bay, the saltmarshes and some bayous. These creatures cannot eat anything larger than Fine in size, but that does not stop them from trying. Oyster Clampers open and close their shells rapidly in order to swim (speed 5 ft., poor) through the water in a mothlike, chaotic fashion. In this manner they accidentally run into swimming creatures.
An Oyster Clamper that touches a creature automatically latches onto the victim with by clamping its shell and biting down with the sharp protrusions in its grooved edges. So while an attached Oyster Clamper can easily be removed, doing so causes 1 point of damage to the attached victim. Otherwise, the oyster releases on its own after 3d20 rounds, causing no damage, and leaving a harmless, painful welt. Each attached Oyster Clamper reduces the Dexterity of the victim by -1 and causes -1 to all attack and save rolls.
Oyster Clampers can swarm if their homes on the water bottom are disturbed. Statistics for such swarms are identical to a locust swarm, except the “fly 30 ft.” movement rate is replaced with “swim 5 ft.”
Oyster Clampers sense gravitational waves, allowing them to predict tides by determining the direction and strength of gravitational forces. During tidal changes, they open their shells to ingest small creatures that pass through them, by turning in the direction of the water flow. This behavior is repeated if removed to an unnatural environment, such as to an aquarium, and thus can be used to predict tidal flow from where the creature was last transplanted from.
Hazard, CR ½