About this 3D model

The -- SWIG IF YA CAN -- JarThe purpouse of a jar's is to be able to drink from it, you thought?Not with this one! It makes it hard for amusement.Serve your victim a drink and have fun.It was inspired by a jar withthe german dialectic inscription "SAUF WONNST KONNST"which translates well to the choosen title.I couldnt find the correct english name of this thing, only a huge lot of german synonyms:(vexierkrug, vexiergefäß, lochkrug, halbekrug, scherzkrug, gaudikrug)If someone knows the correct english term, please comment.All my guesses (puzzling jar, TRY jar, ..) where obviously wrong.Btw.: if you know the open secret, please dont spoil it in the comments.