Plasma Beasts is a weapon manufactured by Grummel Net Industries in Tools of Destruction. A mine-launching weapon, it launches synthetic blobs known as Plasma Beasts to the ground, which lay dormant until sensing an enemy in close proximity, at which point they throw themselves at the enemies.
The Plasma Beasts can be acquired on planet Cobalia when reaching the Cobalia Spaceport for 15,000 bolts. It can be upgraded to the Plasma Stalker with use. Additionally, it can be upgraded with Raritanium, providing it more damage, more ammo, bigger area, more raritanium, and its special upgrade, Proximity Sensors, which allow it to sense enemies from a further distance. In challenge mode, the Omega Plasma Stalkers upgrade can be purchased for 3,000,000 bolts.
The weapon is wrist-mounted, and contains a yellowish canister with green slime - which becomes the Plasma Beast when launched.
The Plasma Beasts themselves are green creatures with a humanoid upper body but no legs. When planted in the ground, they appear as a single green stalk. Plasma Beasts, when defeated, leave behind a gooey substance that appears similar to Gelatonium (and will be eaten by Tumfoids when dropped).
The Plasma Beasts weapon functions as a mine-launching device, in which the beasts throw themselves at enemies that are close. After throwing themselves at enemies, they will explode, affecting a decent area around the enemy they attacked and dealing good damage. While the Plasma Beasts are designed as a strategic weapon to be used defensively to protect Ratchet, they can also be used offensively to attack enemies. The Plasma Beasts has a similar role to the Nano-Swarmers, though it deals quicker damage in bursts rather than sustained damage over time. However, due to the nature of enemies that appear later on, and how quickly its damage drops off, the Plasma Beasts therefore becomes outclassed by the Nano-Swarmers.
As the Plasma Beasts upgrade, its damage increases by 15% each time. Of the Raritanium upgrades available, more damage and bigger area provide the most use to the player, though more ammo can be useful, and more raritanium can make for a nice bonus. Proximity Sensors is a powerful upgrade that allows it to be more useful offensively but also makes it easier to spread the Beasts out across a larger area. When upgraded to Plasma Stalkers, the beasts are now able to burrow through the ground, meaning they no longer need to be placed so defensively and can transition to a more offensive weapon (although it still does not compete well with more powerful offensive weapons).