Gishki Grimness

When this creature is in your hand or on the battlefield, when you cast a blue Ritual
sorcery spell, you can treat this card's mana value
as any value.
When Gishki Grimness enters the battlefield, you
may search your library for a non-Ritual, non-
Xyz Gishki creature card, put it onto the battlefield, then shuffle your library. If you put a creature card onto the battlefield this way,
creatures you control can't attack this turn,
unless they are Ritual creatures.