初祖スリヴァー
伝説のクリーチャー — スリヴァー
続唱（あなたがこの呪文を唱えたとき、コストがこれより低く土地でないカードが追放されるまで、あなたのライブラリーの一番上からカードを１枚ずつ追放する。あなたはそれをそのマナ・コストを支払うことなく唱えてもよい。追放したカードをあなたのライブラリーの一番下に無作為の順番で置く。）
あなたが唱えるスリヴァー・呪文は続唱を持つ。
Illustrated by
Modern Horizons#200MythicJapaneseLegality
Rulings
The First Sliver’s last ability only applies while it’s on the battlefield. If The First Sliver’s own cascade ability lets you cast another Sliver card, that Sliver won’t have cascade.
The cascade ability triggers when you cast the spell, meaning it resolves before the spell. It resolves even if the spell is countered. If you cast the card exiled by the cascade ability, that spell will go on the stack above the spell with cascade. You exile the cards face up. All players will be able to see them.
You don’t have to cast the last card exiled by a cascade ability. If you choose to do so, you cast it as a spell. It can be countered, and any abilities that look for spells cast (such as cascade, if that spell has cascade) can see it.
If a spell has 
in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
If you cast a card “without paying its mana cost,” you can’t choose to cast it for any alternative costs. You can, however, pay additional costs. If the card has any mandatory additional costs (such as that of Lesser Masticore), you must pay those to cast the card.
If a spell has multiple instances of cascade (for example, if you cast a second The First Sliver), each instance of cascade triggers and resolves separately. The spell you cast due to the first cascade ability will go on the stack on top of the second cascade ability. That spell will resolve before you exile cards for the second cascade ability.