“Elephant Statue of Disaster” must be sent from the owner’s hand to the owner’s Graveyard in order for its effect to activate.
“Elephant Statue of Disaster”’s effect can be activated during the Damage Step.
“Elephant Statue of Disaster”’s effect activates when sent from the hand to the Graveyard by the effect of “Last Turn” or “Chaos Emperor Dragon - Envoy of the End”.
You can use “Barrel Behind the Door” against the effect of “Elephant Statue of Disaster”.