Sounds a bit too much like shock and awe, but this is a method used to precook items (usually vegetables, with the exception of starchy ones, like potatoes) that would not cook through in a quick stirfry, or for when you want to prepare something ahead and quickly finish the cooking later. It’s also a great way to set that bright green color for vegetables you want to serve not-quite-raw (broccoli, asparagus, green beans…).
Blanch – cook slightly (NOT until cooked through) in boiling water.
Shock – immediately plunge just-blanched vegetables into ice water: this halts the cooking process and sets the color. As soon as the vegetable is cold, drain and let dry, or you will end up with soggy veggies and a huge splattering if you are using them for stirfry.