Skilled Dark Magician (DR1-EN120) - Dark Revelation Volume 1 Unlimited

Each time you or your opponent activates 1 Spell Card, put 1 Spell Counter on this card (max. 3). You can Special Summon 1 Dark Maagician from your hand, Deck, or Graveyard in face-up Attack or Defense Position by offering this monster with 3 Spell Counters as a Tribute during your Main Phase.