I have loose stool with a look like fat , mucus in it .could it be puss coming out with poop? what makes this happen?it's the first time i'm seeing it

Mucus or ? on stool: Mucus discharge occurs in up to 50% of patients with irritable bowel syndrome, with or without pain. Mucus may also be produced in response to partial obstruction, chronic constipation, rectal dysfunction, infection, ; even from secretory villous tumors of the rectum. But you're not sure if the substance seen is fat or pus so at the very least blood/stool studies ; further evaluation is warranted.