In celebration of this thread's resurrection, I'm posting another monster of my own. Enjoy!
Fiendish Cattle
Colossal Beast
Hit Dice: 30d10+270 (435 hp)
Initiative: -3 (-3 Dex)
Speed: 5ft
AC: 3 (-8 size, -3 Dex, +4 natural)
Attacks: Bite +30 melee
Damage: Bite 4d6+24
Face/Reach: 40ft by 90ft/20ft
Special Qualities: Fast healing 5, nutritious
Saves: Fort +27, Ref +15, Will+9
Abilities: Str 42, Dex 5, Con 28, Int 2, Wis 10, Cha 3
Skills: Spot +5
Climate/Terrain: The Abyss, Gehenna, The Nine Hells
Organization: Herd (1-20)
Challenge Rating: 21
Treasure: None
Alignment: Always neutral
Advancement: none
Fiendish cattle are massive mounds of flesh bred by the demons, devils and yugoloths to feed Blood War armies.
A fiendish cattle (yes, “cattle” in this case is singular) looks like a massive lump of meat, about 40 feet wide, 90 feet long and 50 feet tall. They have no legs, but instead ooze along on their massive bellies. This mass is not fat, as the fiends need to keep fit, but is instead muscle. Fiendish cattle meat is delicious and nutritious. Instead of plants, fiendish cattle eat rocks, soil and whatever else comes their way, including flesh if need be. Demons often feed their cattle with the corpses of their fallen foes. The cattle were magically engineered from Prime cows to heal quickly. This is so they can be re-used; the fiends lop of a mass of flesh from the cattle, than it has grown back in a matter of minutes.
Combat
Fiendish cattle are very docile creatures and only attack if very provoked (after the loss of about 200 hit points). In combat they use their massive jaws.
Nutritious (Ex): The flesh of fiendish cattle is very nutritious and is completely converted into energy by the metabolisms of outsiders and humanoids alike. A creature that eats fiendish cattle meat gains a +1 bonus to all of its attack rolls and saving throws for 24 hours. Eating more fiendish cattle meat does not have a cumulative effect.