Mine is "guinea pig" originating in andes (not guinea) and them being not-a-pig type, whole thing is just wrong.
They also just have lots of strange names in different languages
In Polish it's "świnka morska", literally "sea piggy" (same in basically all Slavic and many central/north Asian languages). Though it was officially renamed "kawia domowa" few years ago because even the superconservative Polish Language Council had enough.