Laser Blaster

The Laser Blaster is an optional upgrade available for E-102 Gamma in Sonic Adventure and Sonic Adventure DX, and later Tails and Eggman in Sonic Adventure 2 and Sonic Adventure 2: Battle. It is a weapon enhancer that allows the user's Lock-On Missiles to release violent explosions upon contact, thus damaging enemies that is near the target.

Sonic Adventure
In Sonic Adventure the Laser Blaster is found within the Egg Carrier, in the Egg Carrier Adventure Field. It is located in the water reservoir that is found in room on opposite side of the armoury in the Egg Carrier's main room. It can however not be obtained before the water pool is drained, which happens after the Egg Carrier crashes into the ocean in E-102 Gamma's story. Once this has happened, head back to the Egg Carrier and into the room where the Laser Blaster is located. The water will be now be gone and the Laser Blaster can be obtained.

Tails
Tails' version of the Laser Blaster is located in Prison Lane, in a room behind a set of bars, next to the Goal Ring. To obtain this upgrade, Tail has to possess the Bazooka, which is needed to break the iron crates that blocks the path to the room. In order to open the bared room, Tails has to destroy the Gun Beetle which is hiding in the upper left-hand corner. This will open the cage and the Laser Blaster can be obtained.

Dr. Eggman
Dr. Eggman's version of the Laser Blaster is located in Iron Gate. In order to obtain the Laster Blaster it is necessary to have obtained the Large Cannon. Right after passing the second Star Post, there will be a room with four ring jars and in front of that room there are two water tanks. Destroy them and it will reveal four iron containers. Destroy them and the Laser Blaster can be found behind them.

Sonic Shuffle
In Sonic Shuffle, Laser Blaster is Gamma's Special Attack when in Battle. This makes it more unique as Laser Blaster is not an item, it is an Attack.

Trivia

 * The Laser Blaster is the only upgrade to return from a previous game, yet not be used by the same character that used it in its debut game.