Signs of the Tistina

Activate this card by targeting 1 face-up monster on the field; Special Summon this card as an Effect Monster (Aqua/LIGHT/Level 10/ATK 0/DEF 0) with the following effect (this card is also still a Trap).
●During your opponent’s turn, when that target leaves the field, destroy this card. During your opponent’s turn, when this card leaves the field, destroy that target.