Dragon Lair-Tunnel

Dragon Lair-Tunnel enters he battlefield tapped.
{t}: Add {b} or {r} .
{3}{b/r}, {t}, sacrifice Dragon Lair-Tunnel: Search
your library for a Dragon card, reveal it
and put it in your hand. Shuffle your library.
"Never dig a tunnel so big you could fit a house in it.
Or a giant.Or a dragon."
- Dwarven lesson on excavation planning