Mariña, Princess of Sunflowers (MP14-EN157) [2014 Mega-Tins Mega Pack]

If exactly 1 other Plant-Type monster you control (and no other cards) is destroyed by battle or by card effect and sent to the Graveyard: You can target 1 card your opponent controls; destroy that target. This card must be face-up on the field to activate and to resolve this effect.