The Plasma Burster is an unlockable Throwable for the Engineer. It appears to be four plasma canisters held together in one group. Based on the color of the canisters and explosions, it is likely the same plasma technology used by the Breach Cutter.
When the Plasma Burster hits the ground it will immediately detonate, creating four medium plasma explosions which detonate in sequence in a line, following the direction it was thrown in. The bursts cannot scale walls and will "bounce" off in the opposite direction if there are more bursts to be created when the line hits a wall.
All four plasma bursts combined to deal 240 (60 * 4) damage.
The Plasma Burster is also able to inflict Fear onto enemies that it doesn't kill.
| Fear Factor