Blast Magician (SBC1-ENA04) [Speed Duel: Streets of Battle City]

Each time a Spell Card is activated, place 1 Spell Counter on this card when that Spell Card resolves. You can remove any number of Spell Counters from this card, then target 1 face-up monster on the field with ATK less than or equal to the number of counters you removed x 700; destroy that target.