S5, E30: Working with Carlos Aragon to introduce "Bueno" to the American market, Darrin looks forward to a trip to Mexico City with Samantha. Larry argues that Senor Garcia, president of the company, will feel slighted if he doesn't meet a top man, and goes to Mexico instead. Recognizing Darrin's disappointment, Samantha zaps Larry's meeting. Garcia is angry when she makes Larry criticize Bueno and Mexico. Aragon suggests they need someone more "simpatico." Larry summons Darrin, presenting him as fluent in Spanish. As Samantha is coaching him, Endora pops in. Annoyed, Darrin insults her, and soon disappears whenever he speaks Spanish. Samantha has her mother remove the spell but warns Darrin not to speak Spanish. During his meeting, Darrin even avoids saying Bueno. Samantha explains he's superstitious. and suggests they call the drink Zap instead. After Endora reverses the spell, Darrin disappears whenever he speaks English. Garcia is pleased with Darrin's Spanish but feels he should speak English for their American customers. Using magic, Samantha has Darrin make a great speech, switching from English to Spanish. Darrin apologizes to Endora, solving his mother in-law problem -- for the moment.