Today's card of the day is Skullclamp which is a one mana equipment with an equip cost of one that gives +1/-1 and when the creature is put into a graveyard you draw two cards. This was powerful enough to be banned in Standard as, in part, it provided far too much card advantage for a very low cost. One toughness creatures with this, or even anything getting removed just multiplies the available options like cutting off the heads of a hydra. A truly broken card that dramatically enhanced a number of low cost aggressive decks at the time and still sees play in Casual and Commander which are two of the only formats it isn't banned in.

In Limited this was a huge bomb that had no drawback, fit in any deck, and at worst drew removal or gave a power boost to a creature. A fairly clear first pick in most decks for Booster and absolute inclusion for every Sealed build.

Constructed: 5.0
Casual: 5.0
Limited: 5.0
Multiplayer: 5.0

Skullclamp
 
Most of the time, Wizards does a great job of balancing cards to make sure things are not unfair. When considering the number of cards they print, the relatively few that they have to ban for being overpowered is impressive. Skullclamp is one of the few that leaves me scratching my head, wondering how they didn't see the abuse of this card coming. 
 
In case you're like Wizards and don't see why this is so good, let's run through it. For one mana, cast Skullclamp. For one more mana, equip this to a creature with 1 toughness. It dies and you draw 2 cards. You've spent 2 mana and basically sacrificed a weak creature. That's already a pretty good deal. Altar's Reap is a perfectly playable card that does just that. But, with Skullclamp, it stays on the battlefield for you to use again. And again. And again. There are lots of ways to produce a good stream of 1/1 token creatures, and there are many ways to bring creatures back from the graveyard repeatedly to sacrifice again. Keep doing this until you draw the final piece to whatever combo you're doing, and it's game over.
 
Even in a deck that doesn't combo out with Skullclamp, putting this on a creature that's going to be in combat or is a prime target for removal gives you card advantage too easily. Throw it on a 2/2 creature (it becomes a 3/1) and attack. The opponent either takes 3 damage or blocks (and likely kills) your creature giving you 2 more cards. In the second main step, equip the clamp to something else, and they have the dilemma of whether or not to attack into a blocker that's going to draw you two cards. With all the cards you're drawing, chances are you won't run out of creatures to attack the clamp to.
 
I'm a little torn as to how to rate the card, since it is banned for all major constructed formats except for Vintage, and I doubt many vintage players are looking here for card advice. Since it is banned and therefore completely useless, I will give it a 1 for constructed, but if it ever gets unbanned, it's back to a 5. In casual, the only thing that keeps it from being a 5 is that people tend to frown on fast, broken combos in casual games, so playing with Skullclamp on a regular basis might get you uninvited from the next casual play get-together. Since it does require a certain type of deck to get the best use, it's good, but not always a top pick in limited. In multiplayer, it's pretty powerful too, but if anyone at the table recognizes the power of the clamp, it just made you target number one.
 
Constructed: 1 (because it's banned - otherwise a 5)
Casual: 4.5
Limited: 4
Multiplayer: 4

Skullclamp is, if nothing else, an interesting story.

What you are looking at is a card that was only legal for around 4 months before it was banned. In just that short period of time, Skullclamp completely took over and dominated every competitive format. Of all the decks that registered for the US Nationals that year, three-quarters of them ran Skullclamp. Most Top 8 decks from various Regionals and Nationals ran 4 copies of it. And the most dangerous part was that it was so unassuming, nobody at the time even saw it coming.

Experts at the time, and even Magic R&D, didn't realize the power of Skullclamp, although for different reasons. You would be forgiven for looking at it and not understand what made it so broken. A +1/-1 'bonus'? Well that's not too great. Who wants to weaken their own creatures, after all? And it doesn't do anything else until the guy it's on dies? The reason R&D let it get through development and hit the streets is actually because they completely missed it. The original design of the card (3 mana casting cost, 2 to equip, no power/toughness change) sucked, so in a meeting a month before the set went off to print someone suggested drastically lowering the mana cost, everyone said fine, and it never really got playtested until it was too late.

The real power, as you might be picking up on, was the incredibly cheap reusable card draw, combined with decks that WANTED their creatures to die, or could pump out a lot of cheap 1/1's or tokens, or both. Elves played this, often with Priest of Titania, pumping out a bunch of cheap ones, maybe tapping them for mana, and then killing all of them with Skullclamp's -1 toughness to draw 2 cards for 1 mana. Repeatably. It might as well have just read "1: Draw 2 cards" in some decks. Goblins played Skullclamp, Tooth and Nail played Skullclamp, Arcbound Ravager + Affinity especially played Skullclamp.

Even when played outside of a crazy combo card draw engine, consider what it can do. When you put this on a creature - which you can do for 1 mana, keep in mind - your opponent will pay the price if they decide to kill it. They have to decide if they want to use that kill spell and give you 2 cards in the process. Field wipe spells like Day of Judgment (Wrath of God at the time) were no longer as effective. Imagine a field where you had 4 creatures with a Skullclamp on each. Wrath of God would draw you 8 cards. And Skullclamp was so easy to get and cast and equip, too. Trinket Mage, Steelshaper's Gift, getting a Skullclamp in the hand was easy.

Imagine this simple scenario. Turn 1, cast Skullclamp. Turn 2, play let's say a 2/2 with first strike. Turn 3, equip Skullclamp, and now you've got a 3/1 with first strike... but not just an ordinary 3/1 with first strike. If you kill this creature, your opponent will draw 2 cards. THAT'S the scary part of this card. Not the combat 'bonus' at all, but the fact that you don't have any easy answers when it's out. You throw this on your best creature and your opponent needs to give serious thought about whether they'd rather take X damage, or let you draw 2 cards. And this is not a one-time decision, as long as Skullclamp is out and you have creatures, it's a decision they'll have to make over and over again. And if you're playing aggro and drawing lots of burn and aggressive creatures and such, you have an incredibly overwhelming advantage when they can't even deal with your threats without helping you. That's why Skullclamp was banned.

It was a powerful card, overlooked by many until it was too late. Even after it hit the scene, a lot of players would scratch their heads going 'Why is this good again?' It required very advanced strategies and combos to be broken, otherwise it was just pretty good, and so a lot of casual players passed it by.

But we'll always remember those 4 months where Magic: The Gathering turned into Magic: Skull Clampening.

Constructed: 5
Casual: 4.5
Limited: 4.5
Multiplayer: 4.5