Very few wild beast symbolize pure insanity and foul temper like the owlbear. A beast born of twisted magic, these creatures spend their lives slaughtering literally any non-owlbear creatures they can get their talons on.

While it's true that D&D and other games that feature owlbears also feature many other overly-aggressive creatures, the owlbear takes the cake. They have a single-minded tenacity to utterly destroy anything that moves larger than a mouse. This likely means that they have been known to assault objects swaying in the wind or things rolling down hills as if their very lives depended on it. This also attributes to their perceived madness, as they have little care about who or what they fight, so long as it ceases to move when they are done.

Their recklessness is only matched by their lack of wisdom and sense and self-preservation. In lemming-like fashion, they will gladly charge through or over anything that stands in their way of their target, to include throwing themselves off a cliff to reach a creature on the opposite side, as so eloquently stated in the AD&D 2ed Monstrous Manual. It's not too far out there to imagine that an owlbear would happily pummel its way through a wall to get to some hapless villager or adventurer.

This madness also makes them fatal when directly encountered. An owlbear will stop at nothing to pursue their target, grabbing at them until they are locked within their crushing grasp. Their ability to grapple targets should be focused on while using these creatures in a fight. This is their primary ability. Once they establish a grapple, the victim takes crushing damage and should also be bitten. This will not cease until the victim or the owlbear is dead. Luck be with any party that encounters a group of these beasts.

The number one reason for adventurers to seek out owlbears is to stop an infestation from taking root near civilization. This is not the only reason, however. Many powerful NPCs, such as wizards will pay a decent sum of gold for owlbear eggs. They are not trainable, however, they serve as excellent guardians, so long as the owner takes suitable precautions.

Recap: The owlbear is a vicious and insane predator that will attack anything, even it it means killing itself in the process. Its ability to grapple is its primary mode of attack and should be used whenever it can. Its mindless thirst for death should be expanded upon by the DM if flavor is important to the campaign.

Thx to  fluffygryphon one of my new writers. So excited to work with him.