Dude:
Giggles
Large Magical Beast (Brown Bear, Grizzly)
16HD
Str 35, Dex 17, Con 18, Wis 12, Int 12, Cha 4
AC 36 (+15 natural, +3 Dex, +5 bracers, +3 amulet)
BAB +12; Grapple +28
Feats: Rapid Strike (Claws), Improve Natural Attack (Claws), MultiAttack (b), Improved MultiAttack
Items: Bracers of Armour +5, Amulet of Natural Armour +3, Belt of Str +4, Slipper of Spider Climb (this one is very important; imagine a 1600x16 pound grizzly diving off a 50ft ceiling at you... *squish*)
This was my Companion Familiar the last time I played an Arcane Heirophant. This was before spells like Fortify/Augment Familiar (the 1hr/level one), Magic Fang, Animal Growth, Fly, Haste...
He basically ended single monster encounters all by himself, and when Animal Growth'd, he even grappled bruisers and won (+36 Grapple check, usually +38 because of Fortify/Augment Familiar). My AH just sat back and buffed his nails after buffing him. His name came from the look on the DM's face the first time I unleashed the full force of this terror on his BBEG.