One of the parts I love about B&T is the templates, which are a really cool way to spice up some monsters. However, I'm sure you can perform some overkill by smashing them all on there. So let's do that.
Here, I present the Legacy of Kur!
Our monster of choice will be a lizardman named Kur. Proud, feral and somewhat adorable. He's a medium humanoid with average intelligence, 2 HD, 13 AC and a bite attack.
For the first template, Kur ran into a bit of trouble and got himself turned into a zombie. He loses his ability to use a weapon, and instead gains a 1d6 damage slam. His speed goes down to 20, but he does become resistant to blunt weapons!
Next, Kur stumbles into some radioactive waste, making him grow in size! We are gonna throw the giant template on him, but with only one size increase. So he is now up to 4 HD, and both his bite and slam increase to 1d8 damage.
Next, he catches the eye of an evil god, who instills him with fiendish power to become a half-fiend! He becomes an outsider and sprouts serpentine wings, allowing him a movement of Fly 40. His armor class goes, which dropped to 12 on account of him losing his ability to use a shield when he became a zombie, goes back up to 13. He also gets an additional claw attack at 1d8 (rules are a bit unclear here, so I'm just giving him that). He also gets about 4 (!) special abilities, which include: a tail whip that deals 1d4 damage and inflicts type 2 poison, telepathy and the ability to use tongues, a 30-ft. aura of fear and the ability to cast one 2nd level cleric spell at will, which will be sound burst.
Then, unable to catch a break, our giant half-fiend zombie lizardmen encounters strange magics and becomes elemental! Fire elemental, to be exact. His attacks deal an additional 1d6 fire damage, his can breathe a 20-ft. cone of fire three times a day that deals 3d6 damage, and he is immune to fire.
Eventually, this uber being now contacts Cthulhu and gains psionic powers, which eventually make him powerful enough to be worshiped as a god in his culture. His intelligence changes to high, can use precognition three times a day, can use shield once per day, can use empty mind three times a day and can use mind thrust three times a day.
Thus, here is our final bastard:
Kur, the Fire Elemental Half-Fiend Psionic Giant Zombie Lizardman
Large Outsider, Chaotic (CE), High Intelligence; Solitary
MV 20 (Swim 20, Fly 40)
ATK 2 claws (1d8 + 1d6 fire) and bite (1d8 + 1d6 fire), or tail whip (1d4 + poison II)
SV F10, R13, W12
XP 2000 (CL 7)
An unlucky average lizardman, Kur is now being worshiped as the god of misfortune by the local lizardman tribe. Standing almost 15 feet tall, his skin is decaying and looks charred, with licks of flame coming off of it. Demonic horns sprout from his head and four draconic wings sprout from his shoulders. Psionic runes also permanently circle around his head. Kur is satisfied to be worshiped as a living god after all he has been through, having his choice of food, wine and women, while also satisfying his blood lust through constant warring with humans.
Kur projects an aura of fear out to 30 feet, and can breathe a 20-ft. cone of fire three times a day that deals 3d6 damage (reflex save for half). He can also let out a mighty roar at will, identical to the sound burst spell.
Special Qualities: Weapon resistance (blunt weapons), immune to fire
Spells: Always on - tongues; At-will - sound burst; 3/day - precognition, empty mind, mind thrust; 1/day - shield