Frobscottle

''He got up from his chair and went to a second
huge cupboard. He opened it and took out a glass bottle
that must have been six feet tall. The liquid inside it was pale green, and the bottle was half full. ''Here is frobscottle!'' he cried, holding the bottle up proud andhigh as though it contained some rare wine. ...
He gave it a shake and the green stuff began to fizz
like mad. ''But look! it's fizzing the wrong way!''
Sophie cried.''