Pathfinder 2 Simple Encounter

1 or more... Viper
At... A rapid waterfall leading underground
They... are searching for a place or person
Possibly... One or more of then is drunk or significantly larger

1 or more... Vampire Bat Swarm
At... A swift river into a small lake
They... are guarding a location or area
Possibly... With them are young or other dependent(s)

1 or more... Crocodile
At... A slow river
They... are relaxing or having a celebration
Possibly... They are part of or sacred to a nearby cult or temple

1 or more... Giant Monitor Lizard
At... A crumbling goblinoid shrine to a power of death
They... are starting or ending a journey or migration
Possibly... They are part of or sacred to a nearby cult or temple

1 or more... Grig
At... A flooded river
They... are searching for the PCs
Possibly... It is windy