Chancellor of the Dross is one of a cycle of five Chancellor creatures from New Phyrexia. In Limited, he was a fun one to have for a couple of reasons. A 6/6 creature with flying and lifelink for 7 mana isn’t too bad, and it definitely qualifies as a bomb. But, the primary reason he was good is if you had him in your opening hand, he had an ability that you could use right at the beginning of the game.
While some of the Chancellors had a better ability than he, being able to immediately make your opponent lose 3 life and gain 3 life is a really useful ability. Starting the game at 23 life while your opponent starts at 17 is a useful weapon to have. Yes, Chancellor of the Dross does have triple-black in his mana cost. But, in Limited, you’d be playing a bunch of Black cards anyway if he’s one of your first picks anyway.
In a 40-card Limited deck, the chances of having him in your opening hand are pretty good. So it’s pretty much worth running him in the off-chance you have him in your opening grip, because even if you don’t, you’ll have access to a powerful beater in the late game. But, in regular 60-card Constructed, the chances aren’t so good. It’s not worth running 4 copies in the rare chance that you’ll be able to gain 12 life and make your opponent start at 8.
In EDH, he can be a fun guy, though. This is because his ability targets each opponent, and not just one opponent. He’s also a Vampire, which is a very popular archetype. At one time, quite a few Olivia Voldaren Commander decks featured a copy of the Chancellor, mostly because his ability scales well in multiplayer. Unfortunately, as better Vampires have been printed, the Chancellor has fallen by the wayside. Still, he’s a powerful beater who gets better in a Vampire Tribal deck. But he’s hardly a must-include.
However, there is one thing the Chancellor of the Dross can do that probably no other card can. If you happen to be paying at the kitchen table or anywhere that regular deck construction rules don’t apply (a format technically known as Freeform), you can actually build a deck of 60 Chancellor of the Dross. You ask, isn’t that a bit absurd? It is, because you should only ever have 4 copies of any given card in your deck besides basic lands.
However, in the case that you can actually run 60 Chancellors, you will always start the game with 7 copies of Chancellor of the Dross in your opening hand. This means you’ll drain your opponent for 21 life. Since you start with 20 life in ordinary Magic, that means you automatically win! This concept was popularized by the Magic: the Gathering YouTuber VedalkenGurl, as seen in this video:
In “real” Magic, Chancellor of the Dross is a cool card that played the role of a bomb in New Phyrexia Limited. He still sees some casual play in Vampire Commander decks, too. But it’s just too awesome to see a deck that runs 60 of a card that really just can’t lose. Although, there are ways to beat 60 Chancellors, as it turns out, but not many.
It’s always awesome to see people break a card in ridiculous ways. Such is the magic of Magic!