Got a weird trans-purple cone part as extra in 71043-1 Hogwarts Castle
It looks like a &quot;short shot&quot; of Minifigure, Utensil Bottle, Erlenmeyer Flask with Trans-Purple Fluid Pattern (pictured below) which is included in the set. I would even say it lacks the Trans-clear &quot;coating&quot; around Trans-Purple piece of the combined element.

Short shot - is a term used in LEGO community to describe an uncommon occurrence of plastic element production, where element is produced with insufficient amount of plastic. There could be various reasons: temperature is too low, lack of plastic supply and other errors during production.