House Duston

When this face-up card on the field is destroyed by your opponent's card (either by battle, and it was face-up at the start of the Damage Step, or by card effect) and sent to the Graveyard: You can Special Summon any "Duston" monsters of your choice from your hand and/or Deck to anywhere on the field, but you must Special Summon an equal number of monsters on each side.