Caca log Share definition Flag A really large stool. A big piece of poop that floats in the toilet similar to how a log in a river would float..too big to flush, the size of the shit becomes a toilet clogger. Ew.. he's such a caca log, he needs to chill. Caca log by MainRain October 13, 2018 0 0 Get merch Get the Caca log mug. Buy Now — $32.95 See more merch