Holly King, Lord of Winter

Whenever a Snow permanent enters the battlefield under your control, if it’s neither
day or night, it becomes night. At the beginning of your upkeep, if it’s night, put a moon counter on Holly King, Lord of Winter.

{3}{t} : Remove X moon counters from Holly King, Lord of Winter. You may cast any spell with converted mana cost X or less from your hand without paying its mana cost.