Ooze, Summoning (CR 4)

Medium Ooze
Alignment: Usually neutral
Initiative: +4; Senses: Listen +9

AC: 17 (+7 natural), touch 10, flat-footed 17
Hit Dice: 5d10+15 (42 hp)
Fort +6, Ref +1, Will +2
Speed: 20 ft., climb 10 ft.
Space: 5 ft./5 ft.
Base Attack +3; Grapple +5
Attack: Slam +5 melee
Full Attack: 2 slams +5 melee
Damage: Slam 1d8+2 plus 1d6 acid
Special Attacks/Actions: Acid, summon monster
Abilities: Str 14, Dex 10, Con 16, Int 10, Wis 12, Cha 14
Special Qualities: fast healing 5, immunity to acid and fire, ooze traits
Feats: Augment Summoning, Great Fortitude; Improved Initiative
Skills: Climb +10, Concentration +10, Hide +8, Listen +9, and Move Silently +5
Advancement: 6-8 HD (Medium); 9-15 HD (Large)
Climate/Terrain: Underground
Organization: Solitary or pair
Treasure/Possessions: Standard

Source: Monster Manual III

Acid (Ex): A summoning ooze secretes a natural acid through it protoplasmic membrane. Each of its natural attacks deals an extra 1d6 points of acid damage.

Summon Monster (Sp): Once per round as a standard action, a summoning ooze can summon a creature as the summon monster I spell (caster level 20th). The summoned creature remains for 20 rounds or until slain. A summoning ooze can summon a maximum of twice its Hit Dice in creatures per day.

For each additional 2 HD of a summoning ooze above 5, the summoning ooze's summon monster ability improves by one spell level (to summon monster II at 7 HD, summon monster III at 9 HD, and so on, up to a maximum of summon monster VI at 15 HD). Each 2 HD gained also increases the summoning ooze's Challenge Rating by 1 (instead of the normal CR per 4 added HD for oozes).

Due to the ooze's Augment Summoning feat, its summoned creatures have a +4 enhancement bonus to Strength and Constitution for the duration of the ability's effect.

Skills: Summoning oozes have a +4 racial bonus on Hide, listen, and Move Silently checks. A summoning ooze has a +8 racial bonus on Climb checks and can always choose to take 10 on a Climb check, even if rushed or threatened.

Summoning oozes are quite perceptive. They prefer to set up ambush situations rather than fight up-front battles. If they can, they position themselves up high away from a preferred battleground, summoning monsters each round down on their prey and only engaging in melee when absolutely necessary.