The Sticky Bomb is a type of explosive used in Call of Duty 2. "Sticky Bomb" is a term used for an field-expedient anti-tank mine made by filling a sock with some form of explosive, attaching a fuse, then sealing the sock and covering it with axle grease to make it "sticky". They were usually attached to the tank's tracks to disable its movement.
Sticky Bombs are used to destroy Panzer tanks in the Russian Campaign in Call of Duty 2 in the missions "Repairing the Wire". Three tanks are destroyed with sticky bombs after repairing the wires. In "The Pipeline", after defending the train station, you are ordered to take out a tank. "Downtown Assault" is the last mission in Call of Duty 2 being ordered to take out tanks. On this mission, you will need to take out two German tanks, one near the broken train and another one in the park that will try to escape you.
In Call of Duty 4: Modern Warfare, the Sticky Bomb exists as an inventory icon in the game files, but is not found anywhere in the game, identical to Thermite. It looks similar to the Sticky Bomb in Call of Duty 2.