Prismasaurus (CR 28)

Huge Magical Beast
Alignment: Always neutral
Initiative: +15 (+7 Dex, +8 Superior Initiative); Senses: Listen +37 and Spot +38

AC: 55 (-2 size, +7 Dex, +40 natural) touch 15, flat-footed 48
Hit Dice: 60d10+660 (990 hp); DR: 10/-
Fort +41, Ref +39, Will +24

Speed: 30 ft.
Space: 15 ft./10 ft.
Base Attack +60; Grapple +79
Attack: Bite +72 melee
Full Attack: Bite +72 melee, tail +67 melee
Damage: Bite 8d10+11/19-20 (+1d6 on critical hit), tail 10d6+5
Special Attacks/Actions: Prismatic emanations

Abilities: Str 32, Dex 25, Con 29, Int 4, Wis 19, Cha 10
Special Qualities: Immunities, prismatic blur, SR 38
Feats: Alertness, Cleave, Combat Reflexes, Dodge, Endurance, Great Cleave, Improved Critical (bite), Improved Initiative, Power Attack, Weapon Focus (bite), Weapon Focus (tail); Epic Feats: Devastating Critical (bite), Epic Endurance, Epic Toughness (Ã—4), Epic Weapon Focus (bite), Epic Weapon Focus (tail), Overwhelming Critical (bite), Superior Initiative
Skills: Listen +37 and Spot +38
Advancement: 61-90 HD (Huge); 91-150 HD (Gargantuan)

Climate/Terrain: Any sunny land
Organization: Solitary or pair
Treasure/Possessions: None

Source: Epic Level Handbook

Prismatic Emanations (Su): The reflected and refracted light from the prismasaurus's crystalline ridge functions very similarly to the prismatic spray spell. Any creature of less than 8 HD that is within 30 feet of the creature is automatically blinded for 2d4 rounds. In addition, any creature within 20 feet of the prismasaurus is randomly struck by one or more rays of light, as determined by the table that accompanies the prismatic spray spell. This effect is as the prismatic spray spell in a 30-foot-radius spread, but is otherwise as cast by a 20th-level caster. The save DC for the prismatic spray effects is 49.

Immunities (Su): It is immune to poison, gases, petrification, and mind-affecting attacks.

Prismatic Blur (Ex): The reflected and refracted light that constantly surrounds the creature blurs the creature's outline and makes it difficult to properly target. All melee and ranged attacks against the creature have a 50% miss chance.