Rule reminder
In complex narratives with multiple time frames, 'come se' clauses must anchor their tense to the verb they modify, not to the overall narrative tense. A trapassato main verb may govern a 'come se' clause that itself refers to an even earlier time — requiring trapassato congiuntivo. A present main verb in a literary present tense context still uses imperfetto congiuntivo for current unreality. Master the principle: tense of 'come se' = relative to the verb it modifies.
The story is set in the past. Main verb: 'aveva guardato' (trapassato). 'Come se' expresses simultaneous unreality. Choose the correct form: «Mi aveva guardato come se io ___ un fantasma.»