Tsumasakiotoshi to Watashi

From MangaHelpers:

One day, a girl named Nagatsuma Saki meets a little creature named Tsumasaki Otoshi. Otoshi's role is to cut off the toes of unsuspecting peoples' shoes, but ordinarily humans are unable to see him. Saki is an exception to that rule, and he finds her pushiness and lack of fear terrifying. Saki seems to show up extremely often while Otoshi goes about his usual business of shoe-snipping. [tethysdust]