Get Behind Me Satan (Mark 8:33): was Satan working through Peter, or is Jesus using "satan" metaphorically?

Winger identifies two possible readings of Mark 8:33. (1) Satan actually planted the idea in Peter's mind and Peter leaned into it — Satan's motive being division between Jesus and the disciples, not preserving Jesus's life. Satan would want Peter to rebuke Jesus publicly to sow discord, not to stop the crucifixion which Satan actually desired. (2) Jesus uses "satan" as a metaphor for adversarial opposition to God's plan — Peter is functioning as an adversary (the literal meaning of satan/adversary), without implying demonic agency behind the thought. No contradiction with Judas: Satan entered Judas to ensure Jesus's death; the rebuke of Peter serves a different divisive agenda.