Encounters by Locale: Cormyrean Marshes - The Vast Swamp

Frog, Giant (CR 3)

Medium Magical Beast
Alignment: Always neutral
Initiative: +0; Senses: darkvision 60 ft. and Spot +1


AC: 14 (+4 natural), touch 10, flat-footed 14
Hit Dice: 3d10+12 (28 hp)
Fort +7, Ref +3, Will +0
Speed: 20 ft.
Space: 5 ft./5 ft. (10 ft. with tongue)
Base Attack +3; Grapple -2
Attack: Tongue +2 ranged, bite +2 melee, or bite +6 melee
Full Attack: Tongue +2 ranged, bite +2 melee, or bite +6 melee
Damage: Tongue grapple, bite 2d6+2, or bite 2d6+6
Special Attacks: Improved grab, swallow whole
Abilities: Str 18, Dex 11, Con 18, Int 2, Wis 9, Cha 6
Special Qualities:
Feats: -
Skills: Hide +4 and Spot +1
Advancement: 4-6 HD (Medium-size); 7-9 HD (Large)
Climate/Terrain: Temperate or warm land, aquatic or underground
Organization: Solitary, or pack (2-5)
Treasure: None

Source: Return to the Temple of Elemental Evil

Combat

Improved Grab (Ex): To use this ability, the giant frog must hit with its tongue. Grabbed victims of Medium-size or smaller are pulled into its mouth on the same round bite attack.

Swallow Whole (Ex): The giant frog can swallow creatures of Small size or smaller the round after a victim grabbed. A swallowed creature can climb out of the frog with a successful grapple check, returning it to the mouth where another successful grapple check, needed to get free. A swallowed creature can cut its way out by claws or a Small or Tiny slashing weapon to 10 points of damage, the frog's interior (AC 14). The frog can swallow only one Small creature, four Tiny, sixteen Diminutive creatures, or thirty-two Fine creatures at a time.

Faerûnian Random Encounters by Region and Locale