Giants...
To build the giants, I took a hill giant, and added 3 levels for BAB and skills/feats. They are proficient in club and thrown boulder, and have the following feats:
Weapon focus (club, boulder)
Weapon specialization (club, boulder)
Far Shot (boulder)
Rage 1x per day
Bouldering (special, only strong enough while
raging)
Bouldering, which none of the giants have done yet, turns a larger-than-normal thrown boulder into an area effect attack. It hits an area roughly 20 feet long and 5 feet wide, and basically punches through and knocks aside everything in its path. The giant has to make a Fort save against exhaustion each time he does this, and he does his normal boulder-throwing damage.
Hill giants normally aren't strong enough (prereq min STR 29), but while raging they can pull it off.
These giants are, generally speaking, monsters in combat. They have 76 hp (slightly lower than strict D&D), plenty of boulders, a range increment around 100 feet, and a better-than-expected BAB (+11/+6 ranged).
Armorcats, I've discussed before, but here's how they work: Take a tiger. Change AC to 11, and add DR 3. Give it an insane +8 bonus to Hide rolls in rocky terrain, and allow it to hide in plain sight when absolutely still (it magically 'blends' its appearance into the surroundings); this is modelled on the gargoyle.
You end up with an ambush master that eats Athans for breakfast, if the Athan is by itself

.