The World's Ugliest Animals
I resisted creating this one for a while because I was thinking it was a bit shallow and that all of God's creatures are beautiful, aren't they? Not really. Anyway, animals don't mind being called ugly, what matters to them is food, sleep and mating, in that order. And when it comes to mating strength and skills usually count for more than beauty.
Rodents are not favored for their good looks but this is an extreme case.
And now for a few that are not necessarily from ugly species but are only some of the ugliest representatives from within their species.