Transformers Animated - Along Came A Spider 2

It's Halloween and Sari introduces the Autobots to Earth's costume-and-candy traditions. However, the entire affair brings up bad memories for Optimus, who is haunted by the ghosts of his past, specifically when he and his fellow bots, the cocky and arrogant [Sentinel Prime] and power-mimicking [Elita One] were looking for a crashed Decepticon ship loaded with energon cubes.