Buggers? - Nissan's minivan Moco didn't do so well in Spanish-speaking markets. Especially green ones. Distributors in Santiago, Chile asked that the vehicle be renamed since Moco is the Spanish word for mucous.
These were printed poster size and mailed inside plastic tubes stuffed with facial tissue.
Saw the Potato? - An American t-shirt maker in Miami printed shirts for the Spanish market which promoted the Pope’s visit. Instead of read “I saw the Pope†(al Papa), the shirts read “I saw the potato†(la papa).
Diarrhea? - According to the Lansing State Journal, Coors "Turn it loose" campaign translated into "Sueltalo", or "Let it loose", as in diarrhea, before the company quickly changed the slogan to "Wont slow you down."