Dust devils are odd creatures that breathe in rocks and dust to fire them at enemies. To fight them you will need level 65 Slayer and be wearing face protection such as a face mask or slayer helmet, otherwise they will rapidly drain your stats and inflict damage at a fast rate. They are located in the Smoke Dungeon near the Desert Bandit Camp, and in a chamber of the Chaos Tunnels. They give 202 Slayer experience when on a Slayer task.
Dust devils are weak against crushing attacks. Depending on your skill levels and available equipment, you might opt for dual-wielding a dragon mace/off-hand dragon mace, or a Saradomin sword. If you do not have a suitable crushing weapon, any decent melee weapon will still be effective.
In addition to their regular drops, dust devils can also drop items from the Rare Drop Table.