Owlbear

No, that's a bare owl.

The first one was more disturbing.

Number Appearing:  One's enough

Size:  Too big

Armor: Fat, feathers, intense burning rage

Resilience:  Very.  Too angry to recognize lethal injuries.

Intelligence:  Not so much.

Communication:  Violence, mostly.

Disposition: Hangry.

Violence:  Very much so.  All the appendages end in sharp.

Enemies:  More or less everything, but especially wizards.

Aims:  Kill.  Eat.  Hopefully in that order.

Peculiarities:  Interact strangely with wizardry.

Treasure:  Not really.  Maybe a tacky rug if you're careful.

Wizards bend Reality in uncomfortable ways.  Owlbears are Reality telling them to stop.  The enormous eyes can see magic, even in complete darkness.  Especially in sorcerous darkness.  Magic is tasty.  Owlbears devour spells as they devour wizards.  If the wizard is particularly alert and starts casting before the chomping starts, they devour spells before they devour wizards.  The magic makes them stronger, angrier, and harder to kill.  Oddly, they'll get the same rush from devouring scrolls, wands, spellbooks, and potions (oftentimes plus the potion effect).  In the absence of sorcery, they are merely nearly silent nocturnal ambush predators that can out-sprint a horse.