The Spinebeam shortbow was released with the Dungeoneering skill. It has the same stats as a yew shortbow. It requires a Ranged level of 40 to wield and can be made by players at level 41 Fletching, requiring some spinebeam branches and a bow string. This bow, along with all other tiers of shortbows, may be obtained as a reward for defeating the Skeletal Trio boss in the occult floors.
It is the best F2P shortbow available in Dungeoneering, and the best overall bow for floors where offensive bonuses are paramount. It is faster and more powerful than its counterpart, the spinebeam longbow, though it does not provide any form of defensive bonuses.