The mystery lineup of hotwheels vehicles was produced by Mattel in 2004 and continues to this very day. The mystery vehicles sport unique paintjobs that some have said to be be better than even the Treasure Hunts line! They stick out from the other hotwheels line ups, due to the car bubble being "blackened" to hide the car, and the ? on the bubble. In 2011, the black blister was done away with. The cars are now (2011 & 2012) packaged in a foil pack. It is easy to identify the car inside. Using the code on the front of the package, you can match it to the chart on the back side.