A five day banana is an obscure term used to denote nothing in particular, but definitely not a five day banana (not even a four day one). Similar to terms such as 'it', 'that', 'thing', 'it', 'stuff' and 'it'. Five Day Banana is also the name of an unsuccessful heavy metal/classical music/mime band, who were not successful because the problem of trying to make the three musical genres work gave each band member a spontaneous aneurysm. Only the band's manager, Captain Kirk escaped, fleeing to Mexico to become an armadillo.