Ep 18. The Dweller in the Depths

In Transformers season 3 episode 18, titled "The Dweller in the Depths," the Autobots continue their fight against the Decepticons. The episode begins with Abominus, the combined form of the Terrorcons, attacking an oil refinery. The Autobots intervene, but the Decepticons escape with the oil they were after.

Meanwhile, underwater in the Sea of Rust, the Decepticons have made a discovery. They've found a powerful ancient creature known as the Dweller, who has been asleep for centuries. However, the Dweller is awakened and begins attacking the Decepticons, causing them to retreat and seek help from the Autobots.

The Autobots, led by Ultra Magnus and Springer, arrive in the Sea of Rust to investigate the Decepticon's claims about the Dweller. Upon arriving, they find the sea is filled with traps and obstacles. They also come across the Protectobots, who are on a mission to recover a sunken Autobot ship.

As the Autobots and Protectobots navigate the dangers of the Sea of Rust, they discover that the Dweller is actually a massive sea monster that has been feeding on the energy of ships for centuries. The Decepticons had awoken the Dweller by accident, and it was now attacking any ship that entered its territory.

The Autobots and Protectobots devise a plan to stop the Dweller before it destroys any more ships. They lure it to the surface with a powerful magnetic device and engage it in battle. The fight is intense, with both sides taking heavy damage.

In the end, the Autobots and Protectobots are able to defeat the Dweller, but they discover something unexpected. The Dweller was not actually an ancient creature, but a giant Cybertronian who had been stranded on Earth for centuries. The Dweller had adapted to the environment of the Sea of Rust and had been surviving by feeding on ships and their energy.

The episode ends with the Autobots repairing the damaged Protectobot ship and using it to transport the Dweller back to civilization. The Autobots hope to learn more about this ancient Cybertronian and discover how it ended up stranded on Earth for so long.