muddy crocodile

When someone fails to flush the deuce they dropped in the public toilet, and then subsequent users of the toilet, rather than flushing it down, continue to urinate on the floating turd until the surrounding water becomes so murky you can only barely see the top of the log emerging from the water.

Also known as a chocolate alligator.

Fucking nasty! I just walked into that stall and somebody left me a muddy crocodile!