From the makers of Chest That Murders You, Wall That Murders You, Floor That Murders You, and Air That Murders You, there's Marble Column That Murders you!
Caryatids are medium-sized constructs with 6 RHD (meaning subpar everything). They get +9 natural armor and hardness 8, making them quite tricky to kill (at least until you hit high levels and those 20 bonus HP fail to make up for the lack of constitution). In addition, any weapon (magical or not) that strikes a caryatid column has a chance to shatter and deal no damage, because Why Even Bother Not Using Spells At This Point.
Ability scores are all over the place: 20 strength, 16 dexterity, and then 6 intelligence and 1 wisdom and charisma. Immunity to ability damage and drain prevents the latter two from being a deadly weakness.
Another notable traits is the ability to turn into a featureless stone column up to 25 ft. tall and 2 ft. in diameter, which a creative player should be able to find some uses for. It's Extraordinary, strangely.
Finally, caryatids are bound to a magic weapon (default a +2 bastard sword), which they can stow into their body and which turns to stone if it leaves the column's hands. I'm assuming that this doesn't impact your WBL, but I'm also assuming that you can't just swap it out with another weapon of equal value (not as problematic as it sounds, given that the column can't actually sell it).
I like these monsters, but six construct HD are a big price to pay and the rewards aren't that great. -0 LA, but not completely unplayable.