Complex sentence: Curly finds what the Stooges believe to be the mummy of Rutentuten in a secret passageway activated by a trap door, but clumsily drops it, crumbling it to dust.
Split into simpler sentences: Curly finds what the Stooges believe to be the mummy of Rutentuten in a secret room, activated by a trap door. When Curly tries to pick it up he clumsily drops it, crumbling it to dust.