My personal fantasy is to get a paint pellet gun - preferably a nice, powerful one - and, as the cyclist lifts his/her/its rump into the air to take careful aim and place the paint pellet deftly in the center of mass leaving a bright green (or blue, or pink, or whatever) splotch of paint for all the world to see.
Of course, I'd never commit such an illegal act...but it does bring a smile to my face and joy to my heart whenever I reflect upon it!