Related Clues:

• Ant, maybe
• Dennis the Menace, for one
• Hanger-on
• Unwelcome guest
• Bothersome person
• Adamant ant?
• Thorn in one's side
• Annoyer
• Aphid, to a gardener
• Exterminator's target
• Termite, e.g.
• Destructive insect
• Vexatious sort
• Irksome sort
• Troublesome insect