Credit to Bhu on rpg.net
Dire Goldfish
Extra Super Biggie Size Magical Beast
Hit Dice: 400d10+9200 (11400 hp)
Initiative: +3
Speed: Swim 50 ft. (10 squares)
Armor Class: 81 (-16 Size, -1 Dex, +88 Natural), touch 0, flat-footed 81
Base Attack/Grapple: +404/+470
Attack: Nibble +423 melee (4d6+72/19-20)
Full Attack: Nibble +423 melee (4d6+72/19-20)
Space/Reach: 200 ft./150 ft.
Special Attacks: Unsettling Presence, Plow
Special Qualities: Dark Vision 60', Low Light Vision, Blindsense, Damage Reduction 60/-
Saves: Fort +228, Ref +207, Will +140
Abilities: Str 80, Dex 8, Con 50, Int 1, Wis 12, Cha 25
Skills: Listen +137, Spot +137, Swim +177
Feats: Alertness, Cleave, Close-Quarters Fighting, Cumbrous Fortitude, Cumbrous Reflexes, Cumbrous Will, Damage Reduction (x20), Danger Sense, Devastating Critical (Nibble), Diehard, Endurance, Epic Fortitude, Epic Prowess (x4), Epic Reflexes, Epic Toughness (x 40), Epic Will, Great Cleave, Great Fortitude, Improved Bull Rush, Improved Critical (Nibble), Improved Initiative, Improved Natural Armor (x41), Improved Snatch, Multisnatch, Iron Will, Large and In Charge, Overwhelming Critical (Nibble), Power Attack, Power Critical (Nibble), Shock Trooper, Snatch, Swim-By Attack, Weapon Focus (Nibble)
Environment: Elemental Plane of Water
Organization: Unique
Challenge Rating: not applicable
Treasure: None
Alignment: Always Neutral
Advancement: 401+ HD (Extra Collosal)
Level Adjustment: ---
"HOLY S___!"
Goldfish collectors know that the larger the bowl you put your goldfish in the bigger it will grow. Someone had the bright idea of taking one to the Plane of Elemental Water to see just how big one could get over time. Bad idea as it turns out. The Dire Goldfish appears to be effectively Immortal. It doesn't age, it does eat, but it doesn't appear to need to.
Plow (Ex): The Dire Goldfish rarely cares about smaller life forms and will just swim through them. Effectively it makes it's full movement, and does a Bull Rush against every creature whose square it enters. They also have to make a DC 246 Reflex Save or take 8d8 damage. They take half damage if they save successfully. For purposes of the Plow the Dire Goldfish is 2 Size categories larger than Colossal. Opponents do not gain attacks of opportunity and cannot stop the Goldfishes movement unless they are at least Colossal size.
Unsettling Presence (Ex): Anything within 1 mile of the Dire Goldfish must make a Willpower Save (DC 217) or be Panicked for 2d6 rounds. If they succeed they are instead Frightened for 2d6 rounds. Save DC is Charisma based.
Immortal (Ex): The Dire Goldfish doesn't need to eat, sleep, breathe, and doesn't age. It is immune to sleep/aging/death effects, disease, poison, mind affecting effects (including Fear and Morale).
Combat: The Dire Goldfish rarely initiates combat unless it is really hungry. At which point it just nibbles away on whatever's biggest and closest. Make sure your faster than other members of the party and it's all good.
As well as being hilarious, I can also imagine doing something semi serious with it. It's fighting a giant whale or something...
Excuse me while I divert my players to the Plane of Water.