Start bye getting any type of staff, and use shoot it at a wall.

But before the actual ray/beam/what-ever-it's-called comes out, open your inventory, activate your scrolls (must be 2 or more), and exit your inventory.

Your staff should be shooting out items!

Glitch: Sometimes, say if it's a Staff of Fireball, sometimes if it hits one of the items, the item will catch fire (fire damage) and will stay like that until you pick it up.