Sticky or squishy mud (or food that's just about as appetizing) is slop. You'll want to wear your tall rubber boots if you're going to walk through the slop on the way to the bus stop.
Farmers feed their pigs slop, a messy, wet mix of various leftovers—and when they do, they can say they slop the pigs. A derogatory way to talk about food that doesn't look very tasty is to call it slop. And you can call sticky, overly sentimental music, writing, or films slop as well. The 15th century definition of slop was "mudhole," from the Old English cusloppe, "cow dung."