Sherlock Holmes Behind the Scenes, pt 14 (Patreon)

The big reveal! 

Dialogue:

Holmes: Good heavens!  Those are the plans to Professor Partington's device!  (pause) Watson--!  Were you the one Kitty Winters saw in the lab that night?  (Behind him, Watson is looking aggrieved and offended.)
Watson: (lunging over their shoulders to snatch at the plans) GIVE ME THOSE PLANS, YOU OLD HAG!

(Watson and Mrs. Hudson are violently struggling over the Plans.  Holmes is trying to pull Watson off with his good arm)
Mrs. Hudson: Doctor Watson!!!
Watson: (snarling incoherently and clawing at the plans and Mrs. Hudson, maybe grasping her collar and she grasps his wrist.)
Holmes: (angrily) What is the meaning of this?!
Watson: (glaring furiously) I'll tell you the meaning of this, you bloody great fool! (or "pillock," a derogatory English term)

(Watson then rips off his head and clothes, revealing a rat on stilts  (Packrat).  The ends of the stilts are raccoon feet.  Holmes scowls,  Mrs. Hudson reacts with shock)
Watson: (In angry triumph) It is I--Professor James Moriarty!