La Taca
Ostensibly the female version of a taco. It's not an actual word in the Spanish dictionary, but it's a fun way to confuse your Spanish-speaking friends.
Person 1: "¿Quieres venir a mi casa a comer la taca?"
Person 2: "¿Qué es la taca?"
Translation:
Person 1: "Do you want to come over to my house and eat la taca?"
Person 2: "What is la taca?"
Person 2: "¿Qué es la taca?"
Translation:
Person 1: "Do you want to come over to my house and eat la taca?"
Person 2: "What is la taca?"