Dire bear

The omnivorous dire bear usually does not bother creatures that try to avoid it, but will aggressively defend a kill or other source of food. It will not hesitate to rip apart anything that might contain something edible.

A typical dire bear is 12 feet long and weighs as much as 8,000 pounds.

Animal Companion

 * Dire bear: Druid level - 12 = 3rd level druid effectivel: +2 HD, +2 Natural Armour, +1 Str&Dex, +2 tricks
 * Abilities: Alertness, Endurance, Run, Toughness, Weapon Focus (claw)

Halfling druid
Enhanced Link (Ex): The halfling druid gains a +4 to ride whenever he uses his companion as a mount, he also passes the Trackless step ability to his mount as long as he is riding it. This ability enhances the standard druid link ability.

Combat
A dire bear attacks by tearing at opponents with its claws.

Improved Grab (Ex)
To use this ability, a dire bear must hit with a claw attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity.