Plasma Energy Chamber
The Plasma Energy Chamber is a reservoir of plasma energy.
Fiction
The Transformers cartoon
According to Optimus Prime, the Plasma Energy Chamber is the foundry where the original Autobots' bodies were forged, millions of years ago. Since that time, every Autobot leader's duties have included guarding the key to the Chamber. The Chamber is located on Cybertron, twelve levels below Generator C.
Unfortunately, the key was stolen during an all-out Decepticon assault on Autobot City. The Rebirth, Part 1 The Autobots managed to get back the key on Nebulos but failed to keep it when Scorponok got into the fray. The Rebirth, Part 2 The Autobots and Decepticons fought back on Cybertron for the key but Galvatron managed to open the chamber and get Cybertron near Earth and caused a huge danger to the Sun. Spike found a way to reabsorb the plasma energy back into Vector Sigma and restore Cybertron to its Golden Age. The Rebirth, Part 3
Beast Wars cartoon continuity
3H comics
The Plasma Energy Chamber was an attempt by the Quintessons at controlling Primus but it failed and created the Trans-Organics. Disclosure
Beast Machines cartoon

Optimus Primal saw a vision that the Plasma Energy Chamber could help them against Megatron and his Vehicon forces. During a desperate hour, where Megatron had defeated all the Maximals with the Key to Vector Sigma. Optimus opened the Plasma Energy Chamber and watched his hand dissolve. End of the Line Optimus and Megatron clashed energies of both super-weapons and eventually, Optimus had a vision of a destroyed Cybertron due to the energies which convinced him to combine both energies and shoot them into the Matrix. Fallout
Exodus
Megatron tried to use the Plasma Energy Chamber to spread his Dark Energon influence across Cybertron. Despite Omega Supreme's efforts, Megatron was successful and continued for the Core of Cybertron. Exodus