Endora and Arthur
Endora and Arthur were brother and sister, and displayed sibling rivalry. Understandably, Endora had her limits for his practical jokes, but did put up with a lot from him.
After spending most of the evening heckling her during her Halloween party (including zapping a wet dead fish into her hands when she was trying to conjure up caviar), she had her breaking point and zapped him into the fountain as a statue replacement. Arthur stood there for some time in the exact pose as the statue, so I'm assuming she arranged it so he couldn't move as water poured down him.
One thing I was surprised at was when he had her dessert squirt a stream of chocolate right into her eye. He really crossed the line, and I thought she have zapped Arthur (and Darrin, for laughing) right into kingdom come. She displayed amazing restraint. (I always wondered if that caught Moorehead by surprise, with the stream hitting her right in the eye. She played it off well.)