Clockwork Dragon [Mirrodin] Resale Promos Set: Stronghold Type: Enchantment Rarity:

Set: Stronghold Type: Enchantment Rarity: Uncommon Cost: {2}{B} Whenever an opponent discards a card

you may put a permanent card with equal or lesser converted mana cost from your hand onto the battlefield

but he gleaned the rudiments of lithomancy from Nahiri

if it wasn't put onto the battlefield with this ability

Clockwork Dragon [Mirrodin] Resale Promos Set: Stronghold Type: Enchantment Rarity:Set: Mirrodin Type: Artifact Creature Dragon Rarity: Rare Cost: {7} Flying Clockwork Dragon enters the battlefield with six +1 +1 counters on it. Whenever Clockwork Dragon attacks or blocks, remove a +1 +1 counter from it at end of combat. {3}: Put a +1 +1 counter on Clockwork Dragon.