tough and hard sounds like an old seed that has been stuck in your guts for a while
if it was a parasite, it would squish pretty easily and the guts would ooze out, i imagine
also it would probably smell pretty raunchy
congratulations on a deep cleanse
a friend of mine who had been vegetarian for over twenty years started doing colonic irrigation and he said he could taste pork when his guts started coming unglued
he was raised on pork
i once did a lung cleanse with miso and daikon
i started coughing up the taste of THC and i hadn't smoked pot in ten years