The Suck Box is the name given to a repository where cards that are no longer used for playing are placed, as opposed to just throwing cards away (or recycling, if you're eco-minded). These are usually the cards that didn't make the cut during the postgame judging, although cards that involve reviving, condemning, and otherwise manipulating cards to and from the Suck Box during gameplay are certainly possible.
Uses[]
Example[]
Why not just throw old cards away? The suck box serves as a powerful resource for teaching new players how to create cards, as it may serve as a list of "what never to do, ever again." It may also serve as a visual reminder to avoid creating suck-worthy cards. Additionally, it makes finding a sneakily broken card that hasn't been suckboxed yet easier to spot, especially if you've had plenty of innocent looking cards that later turned out to be ridiculously over-powered.
Exile[]
The suck box is this box where the bad cards go, never to be seen again. It is very hard to take cards out of the suck box, especially when playing with more competitive rules, however this doesn't mean that cards can't be sent into it. One very easy and effective way to permanently remove a card from play is to send it to the suck box, as it is incredibly unlikely that your opponents will have a response to that without negating or even reversing the effect of your card.
Blinking[]
Blinking a card means to suckbox it then immediately play it from the suck box. This is done to use any abilities on the card (such as "Target player loses 100 points") multiple times, and to trigger abilities of other cards (such as "Whenever a stickman is played in your play area, draw 2 cards"). This use is more likely to be used as a combo, however it can lead to some interesting results. Blinking a card doesn't have to be instantaneous, you could receive the card back at the end of your turn. The suck box is uniquely fit to be used this way, as the discard is easily stolen from or even shuffled back into the deck.
Winning Conditions[]
All of the broken, busted, and munchkin cards are in the suck box. There is bound to be a card that plainly says "The game ends with you as the sole winner." Without competitive rules, it is relatively easy to pull out the best and most horrendous cards and stomp the floor with them. Though, if you do decide to be a Munchkin, at least make it interesting to watch.