During either player's turn, you can activate "Magical Musket" Spell/Trap Cards from your hand. If a Spell/Trap Card is activated in this card's column: You can Special Summon 1 Level 4 or lower "Magical Musket" monster from your Deck in Defense Position, except "Magical Musketeer Starfire". You can only use this effect of "Magical Musketeer Starfire" once per turn.