Tolaria West enters the battlefield tapped.
{T}: Add {U}.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with mana value 0, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)
Cards with mana cost {0} (like Pact of Negation) and cards with no mana cost (like Ancestral Vision and Tolaria West itself) have mana value 0.
Cards with mana cost {X}, {X}{X}, or {X}{X}{X} have mana value 0.