Cockatrice ArrowsThese arrows are fletched with cockatrice feathers. As such, they must be handled with gloves to avoid petrifaction. When shot at an enemy, they do normal damage, then provoke a HT-10 roll to avoid turning to stone, along with all carried and worn gear. The HT roll is at +1 per point of DR not penetrated, and is also given a modifier equal to SM (since it's harder to turn larger things to stone). Magic resistance does not add to the roll. The arrow is turned to stone as well, meaning each can only successfully be used once.
The arrows are otherwise normal, and can be enchanted normally. For obvious reasons, most arrows with cockatrice fletching bear bodkin points.
They are effectively priceless, as only a rare few enchanters know the trick of handling the feathers without being turned themselves and yet imbuing the effect on the arrow as a whole. If found on the open market, they might go for $10,000 per arrow.
Rumours persist of other similar arrows, made from the eggteeth of basilisks or like substances. Some even whisper of a bow whose string is made from the sinew of a medusa that confers this effect on all arrows fired from it.
This could also work as a sort of trap for greedy uncareful delvers, but I'd be very careful with this and make it clear that the feathers on those arrows inside that chest you just found are weird, and hey, are you sure you don't want to make a Hidden Lore (Magical Items) roll?