Ghostrick Yeti [AC18-EN004] Super Rare Thunder also they have their effects

also they have their effects negated

If this card is sent from the field to the GY: You can make all "Gouki" monsters you currently control gain 500 ATK until the end of this turn

When this card inflicts battle damage to your opponent: You can target 1 card your opponent controls

If you controlled a Level 5 or higher “Harpie” monster at activation

treat it as Level 6

Ghostrick Yeti [AC18-EN004] Super Rare Thunder also they have their effectsSet: Advent Calendar 2018 Card type: Effect Monster Rarity: Super Rare Attack: 300 Defense: 2000 Can not be Normal Summoned , unless you control a " Ghostrick " monster . Once per turn : You can change this card to face down Defense Position . When this card is flipped face up : You can target 1 "Ghostrick" monster on the field ; this turn , it can not be destroyed by battle or card effects.