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Constantly follow him around muttering made up words so He thinks you're doing a spell.
Bring him a frog and tell him its Arthur.
Ask him if he is such a great magic hunter why you can't you see the one Sorcerer in front of him?
If he questions you about 3 just smirk and walk away.
Pay Merlin to die his hair green.
Take the Dragon out of the dungeons
Pay someone to walk around in Black armor and tell him his Brother in law rose from the dead again.
Tell him Arthur is seeing Sophia agene and that they tried to elope.
Have Gwen and Merlin fallow him around singing Show tunes
Ask him if he is a little to attached to his Ward
A/N Remember to run really fast after doing any of these because he will probably wont to arrest You.