The Grinch

The Grinch is a 53-year old Half-Ogre Bugbear that lives in the mountains just North of the town of Whoville. He is, or at until recently was, incredibly hostile toward the Who's and their Midwinter holiday festivities, going so far as to steal gifts, food, and decorations in an attempt to disrupt the celebration.

The Grinch

Male Half-Ogre Bugbear
CR: 3     Large Humanoid (Giant, Goblinoid)      
HD: 3d8+9     Hp: 25
Init: +0   Spd: 40'  AC: 16 (-1 size, +7 Natural), t: 9, ff: 16
Attacks: (BAB +2, Grap +15); +10 Unarmed: 1d4+9
SA: - -
SQ: Darkvision 60', Giant Blood, Scent
Align: NE (NG by end of book/movie)
Saves: Fort +4, Ref +3, Will +1
Str: 27, Dex: 10, Con: 17, Int: 10*, Wis: 10, Cha: 7
Skills: Bluff +2, Craft (Sewing) +2, Disguise +2, Handle Animal +0, Listen +4, Move Silently +6, Spot +2
Feats: Alertness, Deceitful
Gear: Sleigh with Dog Harness, Sewing Kit, Sacks of Assorted Sizes, "Santy Claus" Hat and Coat

Environment: Temperature Mountains (just North of Whoville)
Organization: Solitary (plus dog)
CR: 3
Treasure: See Gear above
Advancement: by Character Class
Level Adjustment: +1

* The Half-Ogre Template carries an Intelligence penalty of -2 but the Grinch strikes me as being fairly bright so I ignored this when adjusting his ability scores and left him with normal Bugbear intelligence. If I was going to assign the Grinch a character class, I would start with Ranger and make the Who's his Favored Enemy and his dog, Max, his animal companion.

• Bugbears gain a +4 racial bonus to Move Silently checks.
• Carrying Capacity: 692/1,386/2,080 - someone who was willing to put forth a lot more effort than I am came up with an answer to the question "How Strong is the Grinch?" Using what he developed and estimating Whoville at a population of about 500, a Large creature with a Str 27 fits just about perfectly.

AD&D stats:

Climate/Terrain: Temperate Mountains (Cave north of Whoville)
Frequency: Unique
Organization: Solitary
Diet: Omnivore
Int: Average, possibly higher
Treasure: Standard
No. Appearing: 1
AC: 3
MV: 12
HD: 3+2 (28 hp)
THAC0: 16
No. of Attacks: 1
Dmg/Att: by Weapon
SA: +4 to damage
SD: Nil
MR: Nil
SZ: L (7' tall)
Morale: Elite (13-14)
Xp Value: 175

Incorporating the Grinch into your campaign: 

The party enters a town near the middle of winter. The inhabitants are in a panic since the Grinch stole the tribute the villagers had set aside as an offering for the local deity of winter. The townsfolk fear reprisals if the tribute is not recovered.