Imp Catcher is one of the shortest and easiest quests in the game. It involves retrieving the stolen magic beads belonging to the Wizard Mizgog and has no skill requirements.
General questing tips: Enable the RuneLite Quest Helper plugin, hold the space bar to quickly skip NPC dialogue, and use number keys to select chat options efficiently.
Time to complete Imp Catcher: Regular accounts can finish the quest very quickly (under 30 seconds) if they buy all the beads from the Grand Exchange, rather than collecting them manually. For Ironmen, bead drops from Imps depend on luck, and completion can take anywhere from 5 minutes to 2 hours. This makes the quest quite frustrating for ironmen.
These items can be bought from the Grand Exchange on normal accounts for roughly 1K GP each. However, ironman accounts have to obtain them themselves.
Killing imps (level 2) is the fastest way to obtain the different beads on an ironman. Imps have a chance to drop each bead at a rate of 1/25.6. A good place to kill them is at Karamja volcano, since there are eight spawns. Watch out for the level 14 scorpions that roam this area. Alternative locations include: east of the Ardougne Monastery, southern entrance to Falador, basement in Kastori

Every 30–120 seconds, there’s a 25% chance an imp will vanish in a puff of smoke and reappear a short distance away. Using Magic or Ranged is advised to minimize downtime while killing them.
Necklace of passage to teleport to the Wizard's tower: It can be bought from the Grand Exchange. Ironman players have to run to the Wizard's tower from Lumbridge.

Mizgog on the top floor of the wizard's tower is shown below
Congratulations! You have completed the Imp Catcher quest. The rewards are shown below.

After completing the quest, players can get additional amulets by giving a full set of beads to Wizard Mizgog.