The Badland's Maelstrom

Whenever a land is tapped for mana it produces
the same amount of a random color or colorless
mana instead.
Whenever a player casts a spell from anywhere
but their hand they may reveal a card from their
hand that shares a type. If the revealed spell has a lesser converted mana cost, they cast that spell
without paying it's mana cost.
Travelers avoid this place for a reason.