Skeletal Warbeast (CR 4)

Large Undead
Alignment: Always neutral evil
Initiative: +7 (+3 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., Spot +5, and listen +6

AC: 14 (-1 size, +3 Dex, +2 natural), touch 12, flat-footed 11
Hit Dice: 8d12 (52 hp); DR: 5/bludgeoning
Fort +4, Ref +5, Will +6
Speed: 50 ft.
Space: 10 ft./5 ft.
Base Attack +4; Grapple +13
Attack: Gore +8 melee
Full Attack: Gore +8 melee and 2 hooves +3 melee
Damage: Gore 1d8+5, 2 hooves 1d6+2
Special Attacks/Actions: Powerful charge
Abilities: Str 20, Dex 16, Con -, Int 2, Wis 10, Cha 1
Special Qualities: immunity to cold, pass without trace, undead traits
Feats: Great Fortitude, Improved Initiative, Run
Skills: Jump +17, Spot +5, and listen +6
Advancement: 9-16 HD (Large)
Climate/Terrain: Any
Organization: Any
Treasure: None

Source: Heroes of Battle

This horselike creature displays an unnatural combination of skeletal parts, including a pair of long, straight horns protruding from its skull.

Created by an evil necromancer for an undead army, a skeletal warbeast has the body of a large warhorse attached to the skull of an oryx (a plains-dwelling antelope with two long, straight horns).

Skeletal warbeasts are more than just animated horned warhorses, though. The great magic used to create these steeds allows them to retain much of the abilities they had in life - speed, strength, and knowledge - while gaining the ferocity of the undead and the supernatural ability to leave no tracks behind.