Ixzan (CR 4)

Medium Aberration (Aquatic)
Alignment: Usually chaotic evil
Initiative: +2 (Dex); Senses: darkvision 120 ft., Listen +6, and Spot +6
Languages: Undercommon and Aquan

AC: 16 (+2 Dex, +4 natural), touch 12, flat-footed 14
Hit Dice: 6d8+12 (39 hp); DR: 10/magic and slashing
Fort +4, Ref +4, Will +6
Speed: 10 ft., swim 40 ft.
Space: 5 ft./5 ft. (10 ft. with tail sting)
Base Attack +4; Grapple +7
Attack: Tail sting +8 melee
Full Attack: Tail sting +8 melee and bite +2 melee
Damage: Tail sting 1d10+3 plus poison, bite 1d8+1
Special Attacks/Actions: Poison, spell-like abilities
Abilities: Str 16, Dex 14, Con 14, Int 11, Wis 13, Cha 15
Special Qualities: Amphibious, illusion resistance, SR 16
Feats: Alertness; Combat Reflexes; Weapon Focus (tail sting)
Skills: Hide +12*, Knowledge (dungeoneering) +3, Listen +6, Spot +6, Swim +11, and Tumble +5
Advancement: 7-8 HD (Medium); 9-15 HD (Large)
Climate/Terrain: Underground aquatic
Organization: Solitary, pair, or pod (3-12)
Treasure/Possessions: Double standard

Source: Lost Empires of Faerûn

Poison (Ex): Injury, Fortitude DC 14, initial damage 1d4 Con, secondary damage 2d4 Con. The save DC is Constitution-based.

Spell-Like Abilities: At will - control water, darkness, levitate; 1/day - charm monster (DC 16), cure moderate wounds (DC 14), fly, haste, inflict serious wounds (DC 15), invisibility, mage armor, magic missile, slow (DC 15). Caster level 6th.

Illusion Resistance: Ah ixzan gains a +4 racial bonus on saving throws against illusions.

Skills: An ixzan receives a +4 racial bonus on Hide checks. *When the creature is in water, this bonus increases to +8.

Ixzans are quite accomplished at hiding and enjoy using abilities such as darkness and levitate to avoid notice. The creature's long, barbed tail drips with deadly poison, and it also possess a number of useful offensive spell-like abilities.

Aquatic Subtype

Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.