Henry Kuttner 
All is Illusion 

Bertram Moore should never have entered the strange little tavern. But, even so, he might have avoided serious trouble had he kept his temper and refused to argue with the belligerent midget with the fuzzy whiskers. Mr. Moore, being Irish, certainly should have suspected something amiss from the moment he walked into the unusual taproom…

A fantasy tale from the classic science fiction author.