The Decepticons used hypnochips to control the minds of human beings, and create and army of slaves to produce a vast supply of energon cubes.
13 seconds sound clip from The Transformers (1984) - The Ultimate Doom: Search (2) TV Series.
You can hear this line at 00:00:36 in the DVD version of the movie.
Quote context
[...]
- With the help of the evil scientist, Dr. Arkeville...
- Spikes father, Sparkplug, is captured by the Decepticons, and turned into a mindless slave.
- And Megatron succeeds in bringing Cybertron into Earths orbit...
- I never thought Id be sad to see Cybertron.
- The Decepticons will triumph!
[...]