Main Trigger De-Digivolve 1 on 1 of your opponent's Digimon. (Trash a card from the top of one of your opponent's Digimon. If it has no digivolution cards, or becomes a level 3 Digimon, you can't trash any more cards.)
Then, if that Digimon's play cost is 4 or less, delete it.
Security Add this card to your hand.