"what was the reaction of the ghost after being insulted by Mr.Otis ?"

The Canterville ghost stood quite motionless in natural indignation, then, dashing the bottle that Mr Otis had offered, violently upon the polished floor, he fled down the corridor while uttering hollow groans and emitting a ghastly green light. When he reached the top of the great oak staircase, a door was flung open to reveal two little white-robed figures who appeared with a large pillow whizzing past the ghost's head. The ghost hastily adopting the Fourth dimension of Space as a means of escape, vanished into the wainscoting and the house became quiet again.