Voir Transformers, The Complete First Season (25th Anniversary Edition) - Episode 10

Optimus Prime assigns the Dinobots to guard a meteorite that contains new and unknown energy. Appealing to Grimlock's simple arrogance, Megatron convinces the Dinobots to attack Optimus Prime and betray the Autobots. When two new Dinobots join the fight and Optimus Prime bravely sacrifices himself to save Grimlock, good may just prevail.