Merking everybody non-stop as they try to snake their way through traffic. Often used while playing Mario Kart as a policy towards the other racers. As they try to snake their way past you, you simply hit them with a shell, banana, bomb, or other item in order to merk them. When done correctly this will drop them back a few places as well as bring shame upon their racing reputation.
When Pat entered first place on his favorite course, Figure 8 Circuit, we all let out a chuckle as I said "Well look who's about to get merked by my blue shell." *I paused, waiting for my shell to hit Pat* "You can call that Merkantalism."