Source Second Darkness Player's Guide
Aura faint transmutation; CL 3rd
This miniature stone stalactite measures 4 to 5 inches long. As a standard action, you can toss a portable stalactite up to any solid surface no more than 20 feet above, whereupon the portable stalactite automatically affixes to the ceiling. If no suitable ceiling exists, the portable stalactite falls at your feet.
Once affixed, the portable stalactite remains in place until you call it back to your hand (a standard action) or until a living creature (except you) walks under it, at which point it drops from the ceiling and makes a +10 attack roll against the target. If it hits, it deals 1d6+1 points of damage.
You can affix as many portable stalactites as you like to an area’s ceiling, but you must leave at least 5 feet of space between each. A portable stalactite can be detected and disarmed as if it were a trap — it’s a DC 20 Perception check to discover, and a DC 15 Disable Device check to safely detach one.