What would you do if one day you had woken up in a world that had erased any trace of your existence and turned you permanently unnoticable by everyone but squirrels and mites?
Your body still needs sustenance, you can get sick or die from usual things, like lack of oxygen, being crushed by a car or winter cold.

I'd probably start smearing up cryptic messages with my fecies in public places - like, if I were to just take a dump in a public area and people would start slipping on my shit, smelling it and stuff, surely they would have to notice my fecies, right? So maybe if I drew something with them.. unless they have to touch them first to actually acknowledge them.. maybe I could start taking dumps all over the city until some secret paranormal organisation would take interest in these "fecies that make you forget that you are smeared with immediately when you stop looking at them and acknowledging their existence" phenomenon, finally leading them up to me and making my life much more bearable, though in a cage no less.
They'd probably lure me in with squirrers as well, those damn old fucks..