Hatchery Spider
Creature — Spider
Reach
Undergrowth — When you cast this spell, reveal the top X cards of your library, where X is the number of creature cards in your graveyard. You may put a green permanent card with converted mana cost X or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Illustrated by
Guilds of Ravnica Promos#132sRareEnglishLegality
Rulings
Hatchery Spider’s ability triggers as you cast it, and that ability resolves before the spell itself. It resolves even if that spell is countered.
If a card in your library has 
in its mana cost, X is considered to be 0.
A land card that produces green mana, even a Forest, normally has no color.
Creature cards with other types, such as artifact creature cards, count for undergrowth abilities.
Because tokens aren’t cards, they never count for undergrowth abilities.