Beast Machines: Transformers (1999)

S01E11 The Key

Tankor stumbles upon a long-lost weapon capable of transforming living beings into cybernetic metal. When Nightscream falls victim to its effects, the Maximals must hurry to find a way to rescue him before he permanently shuts down. The clock is ticking as they work together to prevent the loss of their friend and the potential consequences of such a powerful tool.