Ghostrick Yuki-onna

"Ghostrick Yuki-onna" can only be Summoned face-up if you control a face-up "Ghostrick" monster.

The monster effect "Once per turn, you can change this card to face-down Defense Position" is an Ignition Effect. (It does not target.)

The monster effect "If this card is destroyed by battle and sent to the GY: You can activate this effect; the monster that destroyed this card is changed to face-down Defense Position, and its battle position cannot be changed" is a Trigger Effect that activates in the GY. (It does not target.)

The monster effect "the monster that destroyed this card is changed to face-down Defense Position, and its battle position cannot be changed" is an optional effect that can be activated at the end of the Damage Step when "Ghostrick Yuki-onna" is destroyed by battle and sent to the GY. (This can be activated not only when "Ghostrick Yuki-onna" is destroyed by an opponent's monster's attack, but also when "Ghostrick Yuki-onna" is destroyed by battle while attacking.)

A monster affected by the monster effect "the monster that destroyed this card is changed to face-down Defense Position, and its battle position cannot be changed" cannot change its battle position as long as it remains in the Monster Zone.