Union Driver (MP21-EN059) [2021 Tin of Ancient Battles]

Once per turn, you can either: Target 1 face-up monster you control; equip this card to that target, OR: Unequip this card and Special Summon it. If the equipped monster would be destroyed by battle or card effect, destroy this card instead. While this card is equipped to a monster: You can banish this Equip Card; equip 1 Level 4 or lower appropriate Union monster from your Deck to the monster this card was equipped to. You can only use this effect of "Union Driver" once per turn.