Poop question

Wondering about something. I keep seeing little black stuff, they look like sesame seeds but they’re black, in my poop. I haven’t eaten sesame seeds lately, I was eating chia seeds for a while but the last time I had them was over a month ago, and I usually soaked them so they weren’t like what one seeing (I remember what that poop looked like lol) there’s A LOT of them too so I’m not sure. My body usually digests food pretty quick like within 6-8 hours I’ll pass what I ate before where most people it takes about 12-24 hours sometimes more. Anyone ever have these or know what they are?! Thanks for any help.