Imp Catcher

Start:
Wizard Mizgog at Wizard's Tower 3rd floor.

Talk to Wizard Mizgog located at the Wizard's Tower 3rd floor. He will tell you he lost his beads (red, white, black and yellow beads). His beads are stolen by the imps of Wizard Grayzag.
Tell him that you will return them for him. Now kill some imps to get beads (can take long). Imps can be found south of Falador and in Al Kharid.
After killing the imp's head back to Wizard Mizgog.