Card Rules: Rulings powered by The Netrep API. Sending 'Wave-Motion Cannon' to the Graveyard is a cost, so when you send it to the Graveyard, it's too late for your opponent to chain 'Mystical Space Typhoon', etc., to destroy 'Wave-Motion Cannon', because 'Wave-Motion Cannon' is already in the Graveyard. Your opponent cannot chain 'Magic Jammer', or use 'Dark Paladin', etc., when you send 'Wave-Motion Cannon' from the field to the Graveyard. Your opponent CAN chain 'Magic Jammer' or use 'Dark Paladin', etc., when you first activate 'Wave-Motion Cannon' (meaning when you place it face-up on the field). If 'Imperial Order' is active on the field, count Standby Phases as normal for 'Wave-Motion Cannon'. You can activate 'Wave-Motion Cannon' (place it face-up on the field) and send it to the Graveyard during the same turn, but it will not do any damage. If the Standby Phase is skipped with 'Solomon's Lawbook' or the turn is skipped with 'Gamble', increase the count for 'Wave-Motion Cannon' anyway. You cannot use 'Pyro Clock of Destiny' with 'Wave-Motion Cannon'. [Re: Barrel Behind the Door] You cannot activate 'Barrel Behind the Door' against a Continuous Spell or Trap Card, an Equip Spell Card, or a Field Spell Card. So you cannot activate it against 'Magical Thorn', 'Dark Snake Syndrome', 'Wave-Motion Cannon', or 'Black Pendant'. [Re: Skilled Dark Magician] When you use the effect of a Continuous Spell Card that is already face-up on the field, such as 'Inspection', or sending 'Wave-Motion Cannon' to the Graveyard, or paying for 'Messenger of Peace', you do NOT place a Spell Counter on this monster. [Re: Skilled White Magician] When you use the effect of a Continuous Spell Card that is already face-up on the field, such as 'Inspection', or sending 'Wave-Motion Cannon' to the Graveyard, or paying for 'Messenger of Peace', you do NOT place a Spell Counter on this monster.