Tonton Streaming Beast Wars: Transformers (1996) S1E8 - Double Jeopardy

After repeated ambushes by the Predacons, this time costing the Maximals a stasis pod, Optimus calls Rattrap's loyalty into question, and sends him off into Predacon territory to look for energon. Once there, he is attacked by Terrorsaur, and offers to surrender... and become a Predacon.