Instructions
Explosive Crate
Equip "Hacker" in your character's third "Perk" slot. You need to purchase "Hacker" using 2,000 COD points. COD points are obtained through battles and in-game contracts. If you don't have 2,000 points, keep fighting until you acquire enough to get "Hacker."
Complete the following tasks to unlock "Hacker Pro": kill 25 enemies with claymores or C4, kill 25 enemies in the radius of your motion sensor or radar jammer, and destroy 10 pieces of enemy equipment. (see References 2)
Select "Hacker" from your character's load-out screen, and purchase the "Pro" version after you unlock it. Upgrading to "Hacker Pro" costs 3,000 COD points on top of the 2,000 you already spent.
Run toward dropped enemy care packages during gameplay, trying to kill the enemy before he retrieves the crate's contents.
Approach the crate and hold the "X" button to booby-trap the crate. Booby-trapped crates explore when the enemy tries to retrieve them, killing the enemy and earning you a crate killcam. (see References 1)
Set a claymore or C4 charge near the crate to ward off further enemy advances, and use your firearm to kill approaching enemies. You need to keep the crate safe until the final kill.
Vacate the area as soon as there is one kill left in the game. At this point, all you can do is hope that an enemy will try to retrieve the crate's contents before another player makes the final kill.
Crate Drop
Ensure "Care Package" is equipped as one of your killstreaks. Your default killstreaks are Spy Plane, Care Package, and Attack Helicopter, so you already have the right equipped killstreaks if you didn't deliberately change them.
Obtain five kills in a row without dying. You must get these kills using your standard weapons and equipment. Unlike "Modern Warfare," the predecessor to "Black Ops," kills earned using your aquired killstreaks do not count toward unlocking the next killstreak. If you have trouble getting five kills while running around the map, consider staying in a corner and using a silenced weapon to rack up kills stealthily. When you get five kills, you are able to use the care package, but don't drop it until the clock runs down further.
Corner an enemy with only a few seconds left on the game clock or when just one kill is left in the game. The final kill can get scooped up quickly by another player, so you need to act fast when you notice there is just one kill or a few seconds left.
Throw your care package toward the enemy. A puff of smoke will let you know where the crate will drop, so try to scare the enemy toward the crate's drop-zone using some suppressive fire. Don't shoot directly at the enemy, as a stray bullet could cause a headshot and end the game. If you get the timing right, the crate drops on the enemy and crushes him. Crate drops are a one-hit kill, so even a completely healthy enemy will die if the crate hits her. (see References 1)