When the control of this face-up card on the field shifts to your opponent, increase your Life Points by 3000 points. This effect can only be used once as long as this card remains face-up on the field.
You can't give an effect monster to the opponent with Creature Seizure.
Shien's Spy is the only card other than Mystic Box that can usefully trigger it currently in Duel Links I believe. (I say usefully, because you could give it to the opponent with a card like Give and Take and use Owner's Seal or something, or steal an opponent's one with a card like Brainwashing Beam.)