on the carpet after using the cat box. He's NEVER did this before so i don't know what caused it. His cat box was clean but he did have a bit of feces on his fur around his bum.
It was probably the leftover crumbs tickling him. You can help him by wiping crumbs off with a paper towel dampened with warm water. If he doesn't scoot anymore then you're home free.
Sometimes, though, impacted anal glands make kitties scoot. Check his bum. If it looks swollen or red at the 4o'clock and 8 o'clock, it might be clogged anal glands. Ick. For that you'll need to see a vet.