Thorns of Violet Poison - Battles of Legend: Glorious Gallery (BLGG)

(This card is always treated as a "Predap" card.)
Target 1 "Starving Venom Fusion Dragon" in your Monster Zone; it cannot attack this turn, also destroy as many monsters your opponent controls as possible with less ATK than that monster, then you can discard your entire hand, and if you do, inflict damage to your opponent equal to the combined original ATK of monsters destroyed by this effect.