The Light of Megiddo (ABC-WD-050 N) [Arcana Battle Colosseum]

[Quickcast] J/resonators your opponent controls must attack this turn if able. Whenever a resonator attacks this turn >>> This card deals 2000 - X damage to it, where X is 500 multiplied by the number of attributes of that resonator. [Mastery] "Refrain, Resident of Wanderers' Castle" (You may rest a recovered card named "Refrain, Resident of Wanderers' Castle" you control rather than pay this card's cost.)