A basic bat in a cave.
Bat, Cave (CR 1)
N Small Magical Beast (Avian)
Init +2; Senses Blindsense 20 ft., low-light vision; Perception +6
AC 14, touch 13; flat-footed 12 (+2 Dex, +1 size, +1 natural)
hp 13  (2d10+1)
Fort +2, Ref +5, Will +2
Speed 15 ft., Fly 40 ft. (good)
Melee Bite +5 (1d6-1)
Space 5 ft.; Reach 5 ft.
Special Attacks Blood Drain, Critical Attack, Screech
Str 9, Dex 15, Con 8, Int 2, Wis 14, Cha 5
Base Atk +2; CMB +0; CMD 10
Feats Toughness*, Weapon Finesse
Skills Fly +13, Perception +6; Racial Modifiers Perception +4
Blood Drain (Su)
Once per day, a cave bat can drain the blood from a target within 30 feet. The target must make a Fortitude save (DC 13) or take 1d8 points of shadow damage and the cave bat is healed for that much. Blue mages may learn this ability as a 1st level spell (Knowledge: Arcana DC 17).
Critical Attack (Ex)
Once every 1d4 rounds as a standard action, the cave bat can inflict more pain than normal. If they succeed at hitting with their bite attack, the damage is 1d6-1 x 1.5 for total damage.
Once per day as a standard action, a cave bat can produce an ear-splitting screech that stuns non-bats in a 20-foot-radius burst. All creatures within the area must make a DC 10 Fortitude save or be staggered for 1d2 rounds. Other bats are immune to this effect. This is a sonic mind-affecting effect. The save DC is Constitution-based.