Fiery Confluence is a four-mana sorcery that can be used for a variety of purposes, though perhaps its best "bang for your buck," especially in Commander, is using the second made three times and dealing a total of six damage to all of your opponents at once
Only two of this one are known to exist, and one sold for $360,000 back in 2001
For example, if you cast Dragonlord Silumgar for 6 mana, then you might hit a Baleful Strix that you can cast for free, and thats being generous
If a card only costs generic mana, like Spire Golem and Frogmite, you can play them for free if you have enough cost reduction
The Honorable Mention for black goes to DEATH PITS OF RATH, which together with red burn and the great gold cards of Invasion can form the basis for a new generation of red-black multiplayer decks
In this box you'll find everything you need to get the fun started