Ugly Casanova is Modest Mouse frontman Issac Brock's side project/collaboration with Brian Deck and Tim Rutili of Red Red Meat and Califone, Pall Jenkins of Black Heart Procession, and John Orth.
Their music is extraordinary- but their backstory is what is really interesting. "Ugly Casanova" is said to be the nom de plume of a deranged Modest Mouse fan named Edgar Graham who broke into the backstage of a Denver show in 1998. Bleeding from the glass shards of the window he smashed to get in and mumbling "This'll do it" under his breath, he presented the band with a notebook full of lyrics, hung around for a while, and then disappeared. Over the next four years Brock fashioned his lyrics into songs with the help of his collaborators- songs which reportedly make up parts of The Moon and Antarctica and Ugly Casanova's first album, Sharpen Your Teeth. Released in May 2002 on Seattle's Sub Pop label, it was perhaps made in the hope that Graham would hear his music and come out of hiding.
That said, it is possible that this story is a myth perpetuated by the band- the lyrics seem to be vintage Brock, with his trademark cryptic, stream of consciousness style. Ugly Casanova delves into the "alt-country" genre (see Yankee Hotel Foxtrot for a criticism of this genre label... nonetheless, it is a close approximation of the band's sound), while retaining the quirky indie rock style of Modest Mouse.