Virus bomb
The virus bomb was created and utilized by Dr. Nuvo Vindi to spread his modified Blue Shadow Virus back into the galaxy.
Description

Round and easily portable, the virus bombs were gray spheres which held canisters of Vindi's Blue Shadow Virus. They had a red circle of light when activated, and a hole for the Blue Shadow Virus canisters.
History
Vindi manufactured many of these bombs to release his air-potent Blue Shadow Virus back into the galaxy. When his plot was discovered, Anakin, Obi-Wan and Ahsoka led a raid on his lab. After Vindi attempted to escape, he remotely activated the bombs, intending on releasing the plague. Fortunately, clone ordnance specialists, who were bomb disposal troopers managed to deactivate all the bombs in time.
Later, Padmé and the Bomb squad discovered that a virus canister was missing from one of the bombs. Vindi's servant droid LEP-86C8, having possession of the missing canister, sneaked back into the bomb room and placed the canister back into a bomb. Before the clone troopers were able to stop it, the droid set the bomb off and the virus was released into the lab, infecting Ahsoka, Rex and the clone troopers, and later Padmé as well. Anakin and Obi-Wan managed to find a cure for the virus in time which was a Reeksa root from Iego.
Behind the scenes
In The Frozen Citadel, there were a few similar virus bombs that contained the deadly Rooze Disease.
Appearances
Star Wars: The Clone Wars – "Blue Shadow Virus" (First appearance)
Star Wars: The Clone Wars – "Mystery of a Thousand Moons"
- LEGO Star Wars III: The Clone Wars (Non-canonical appearance)
Sources
The Clone Wars Episode Guide: Blue Shadow Virus on StarWars.com (content now obsolete; backup link) (First identified as virus bomb)
The Clone Wars Episode Guide: Mystery of a Thousand Moons on StarWars.com (content now obsolete; backup link)