Related Clues:

• Arborist's concern
• See 18-Across
• Fly, e.g.
• Annoying person
• Little brother, often
• Royal pain
• Exorcism target
• Irritant
• Exorcist's target
• Exorcist's prey
• Unwanted visitor
• Bundle of energy
• Exorcist's quarry
• Ant, maybe
• Little devil