A spider fang was a magic dagger with the power to create and cut through webs.
It was black or dark purple in color.
It was a magical +1 dagger. It had the ability to cut through natural and magical webs without getting stuck, allowing the wielder to move through webbed areas with more ease.
Once per day each, it could both weave a web and a curtain made of cobwebs. This was 10-feet-square (3 meters) and was suitable for hiding or concealment. If a curtain was created and a creature touched it, it collapsed and caused the creature acid damage.