A Tracer is the vortex shaped trail of webster residue left in the toilet bowl after a large deuce has been flushed. As the Cosby nugget circles after flushing, its relatively heavy weight causes it to drag. Its greasy composition leaves a visible residue that subsequent flushes will not remove. A Catchers mitt can greatly alleviate the Tracer's effect. This situation will be more pronounced in individuals that consume largely Hispanic or deep fried diets.
Dude, you need to cut down on the KFC. You're leaving Tracers in the bowl!