Megaloceros (CR 4)

Large Animal
Alignment: Always neutral
Initiative: -1 (Dex); Senses: low-light vision, scent, Listen +7, and Spot +6

AC: 14 (-1 size, +1 Dex, +4 natural), touch 10, flat-footed 13
Hit Dice: 6d8+18 (45 hp)
Fort +8, Ref +6, Will +5
Speed: 40 ft.
Space: 10 ft./5 ft.
Base Attack +4; Grapple +13
Attack: Gore +8 melee
Full Attack: Gore +8 melee
Damage: Gore 1d8+7
Special Attacks/Actions: Improved grab, stampede, toss
Abilities: Str 20, Dex 12, Con 16, Int 2, Wis 11, Cha 5
Special Qualities:
Feats: Alertness; Endurance; Run
Skills: Listen +7 and Spot +6
Advancement: 7-12 HD (Large); 13-18 HD (Huge)
Climate/Terrain: Cold marshes
Organization: Solitary or herd (6-20)
Treasure/Possessions: None

Source: Frostburn

Improved Grab (Ex): To use this ability, the creature must hit a Medium or smaller opponent with its gore attack. If it gets a hold, the megaloceros scoops up the opponent with its antlers and can toss it aside.

Stampede (Ex): A frightened herd of megaloceroses may flee as a group in a random direction (but always away from the perceived source of danger). They literally run over anything of Large or smaller size that gets in their way, dealing 1d12 points of damage for each five megaloceroses in the herd (DC 18 Reflex save half).

Toss (Ex): A megaloceros can vigorously shake any creature caught in its horns and fling it in a random direction. Resolve the toss as a bull rush maneuver (+9 check modifier), except that there is no attack of opportunity, since the megaloceros has already grabbed its foe when it tries to toss the victim. The megaloceros does not need to move with its foe in order to throw its foe more than 5 feet. If the tossed victim beats the megaloceros's Strength check, he remains in his current square with no ill effects and is not grappled any longer. Tossed victims take impact damage on landing as if they had fallen a distance equal to the distance they were tossed.

Scent (Ex): A megaloceros can detect opponents within 30 feet. The exact location is not revealed unless the creature is within 5 feet.

Megaloceroses prefer to avoid combat, except during mating season, when males are extremely aggressive and territorial, and during the spring calving season, when female megaloceroses are extremely aggressive in defense of their young.

Megaloceroses typically charge the most obvious or brightly colored target, attempting to gore and toss it, then return to trample and finish it. When an entire herd is threatened, the young males sometimes charge two and three together against a threat.