Stave Sling (Fustibalus)
The staff sling, also known as the stave sling, fustibalus (Latin), fustibale (French), is made from a wooden staff with a sling attached at one end. The sling is constructed of rope with a pouch of some sort to hold the projectile. One end of the rope is attached firmly to the staff, the other end is formed into a loop that slips over the end of the staff.
Staff slings provide an easy way to throw fairly heavy projectiles a great distance. The projectile travels at a very high arc, and lends itself to flying over walls and other obstacles.
Staff slings work on the same principles as a trebuchet and can be thought of as a one man siege engine.
Staff slings were in use well into the age of gunpowder as grenade launchers, and were used in ship-to-ship combat to throw incendiaries.
Deeper Dive
Video: Making a Staff Sling https://youtu.be/FN3mztvclHk